Colored mask combined with selective area deposition

ABSTRACT

The invention relates to a process for forming a structure comprising (a) providing a transparent support; (b) forming a color mask on a first side of the transparent support; (c) applying a first layer comprising a deposition inhibitor material that is sensitive to visible light; (d) patterning the first layer by exposing the first layer through the color mask with visible light to form a first pattern and developing the deposition inhibitor material to provide selected areas of the first layer effectively not having the deposition inhibitor material; and (e) depositing a second layer of functional material over the transparent support; wherein the second layer of functional material is substantially deposited only in selected areas over the transparent support not having the deposition inhibitor material.

CROSS-REFERENCE TO RELATED APPLICATIONS

Reference is made to commonly assigned U.S. application Ser. No.11/986,155, filed concurrently by Irving et al. and entitled, “COLOREDMASK FOR FORMING TRANSPARENT STRUCTUES,” U.S. application Ser. No.11/942,780, filed concurrently by Irving et al. and entitled“PHOTOPATTERNABLE DEPOSTION INHIBITOR CONTAINING SILOXANE,” U.S.application Ser. No. 11/986,102, filed concurrently by Irving et al. andentitled “MULTICOLOR MASK,” U.S. application Ser. No. 11/986,068, filedconcurrently by Irving et al. and entitled “INTEGRATED COLOR MASK,” U.S.application Ser. No. 11/986,189, filed concurrently by Irving et al. andentitled, “GRADIENT COLORED MASK,” and U.S. application Ser. No.11/986,088, filed concurrently by Irving et al. and entitled,“MULTICOLORED MASK PROCESS FOR MAKING DISPLAY CIRCUITRY.” All theabove-identified applications incorporated by reference in theirentirety.

FIELD OF THE INVENTION

The invention relates to a colored masking technique useful for formingelectrical and optical components.

BACKGROUND OF THE INVENTION

Manufacture of many electronic components, including flat paneldisplays, RFID tags, and various sensing applications, relies uponaccurately patterning layers of electrically active materials applied toa relatively large substrate. These products are composed of severallayers of different patterned materials, where it is important that thelayers be in specific registration. The reasons for patterning accuracyare twofold. First of all, patterned features must be reproduced acrosslarge areas of a substrate while having precise control over theirdimensions. Secondly, products built with these features typically arecomposed of several layers of different, but interacting patternedlayers, where it is important that the layers be in specificregistration or alignment.

Traditionally, the precise layer alignment required for fabrication ofelectronic components and devices is accomplished using conventionalphotolithography. An electrically active layer and a photoresist layerare deposited on a substrate, the position of an existing pattern on thesubstrate is detected, and an exposure mask is aligned to that existingpattern. The photoresist is exposed, developed, and the electricallyactive material is etched. Small variations in temperature and humidityin this precise operation may be enough to introduce alignment errors;rigid glass substrates are used with stringent environmental controls toreduce these variations. At the other extreme, conventional printingtechniques such as offset lithography, flexography, and gravure printingalso apply multiple layers at extremely high speeds, although atsubstantially lower overlay accuracy.

There is a growing interest in advancing printing technology towardfabrication of thin film electrical components (such as TFTs) onflexible or plastic substrates. These substrates would be mechanicallyrobust, lighter weight, and eventually lead to lower cost manufacturingby enabling roll-to-roll processing. In spite of the potentialadvantages of flexible substrates, there are many issues affecting theperformance and ability to perform alignments of transistor componentsacross typical substrate widths up to one meter or more. In particular,for example, the overlay accuracy achievable using traditionalphotolithography equipment can be seriously impacted by substitution ofa flexible plastic substrate for the rigid glass substratestraditionally employed. Dimensional stability, particularly as theprocess temperature approaches the glass transition temperature (Tg) ofsupports, water and solvent swelling, anisotropic distortion, and stressrelaxation are all key parameters in which plastic supports are inferiorto glass.

Typical fabrication involves sequential deposition and patterning steps.Three types of registration errors are common in these fabricationprocesses: fixed errors, scale errors, and local misalignments. Thefixed error, which refers to a uniform shift of one pattern to another,is typically dominated by the details of the motion control system.Specifically, mechanical tolerances and details of the systemintegration ultimately dictate how accurately the substrate may bealigned to a mask, or how accurately an integrated print device may bepositioned with respect to a registration mark on a moving web. Inaddition to fixed errors, scale errors may also be substantial. Errorsin pattern scale are cumulative across the substrate and arise fromsupport dimensional change, thermal expansion, and angular placementerrors of the substrate with the patterning device. Although the motioncontrol system impacts angular placement, pattern scale mismatch islargely driven by the characteristics of the support. Thermal expansion,expansion from humidity or solvent exposure, shrinkage from hightemperature exposure, and stress relaxation (creep) during storage ofthe support all contribute to pattern scale errors. Further, localpattern mismatch arising from nonisotropic deformations may also occur,particularly since the conveyance process involves applying tension. Aflexible support used in roll-to-roll manufacturing will typicallystretch in the conveyance direction and narrow in width.

There are several approaches to address the registration problem forfabrication of electronics on flexible substrates, but at this point aleading methodology has yet to emerge. Attach/detach technology has beenexplored by French et al, wherein a flexible substrate is laminated to arigid carrier and runs through a traditional photolithographic process(I. French et al., “Flexible Displays and Electronics Made in AM-LCDFacilities by the EPLaRTM Process” SID 07 Digest, pp. 1680-1683 (2007)).Unfortunately, these technologies ultimately produce a flexibleelectronics component only with the cost structure of current glassbased processing. US Patent Publication No. 2006/0063351 by Jaindescribes coating the front side and back side of a substrate with oneor more resist layers that may be activated simultaneously to impartdistinct pattern images within each resist layer. The precoatedsubstrate is inserted between a set of prealigned masks, oralternatively a dual wavelength maskless direct laser writinglithography system is used, to simultaneously expose the front and backsides. Active alignment systems to detect previously existing patternsand compensation schemes for deformation have also been suggested inU.S. Pat. No. 7,100,510, by Brost et al. With this approach, instead ofattaining accurate pattern overlay by maintaining tight specs on supportdimensional stability and strict environmental control, the motioncontrol system performs multiple alignments per substrate to compensatefor distortion. The proposed solution of Brost et al., to adapttraditional printing equipment for active alignment, may be viewed asexchanging the lens, mask, and lamp of a modem stepper with anintegrated print device. It is difficult to imagine significantequipment cost difference or throughput advantage, particularly if theadded task of distortion compensation is included. A fabrication costadvantage would likely come primarily from materials usage savings orremoval of expensive vacuum deposition steps.

Another approach, which would potentially enable high speed processingwith low capital investment, is to employ a self-aligning fabricationprocess. In a self-aligning process, a template for the most criticalalignments in the desired structure is applied in one step to thesubstrate and from that point forward alignment of subsequent layers isautomatic. Various methods have been described for fabricatingself-aligned TFTs. Most of these methods allow self alignment of onelayer to another layer, but do not significantly remove the need forvery sophisticated alignment steps between several layers. For example,the gate electrode in some a-Si TFT processes is used as a “mask” toprotect the channel area from doping and laser annealing of the siliconon either side of the channel region. The concept of self-alignedfabrication can be understood from U.S. Pat. No. 5,391,507 by Kwasnicket al., U.S. Pat. No. 6,338,988 byo Andry et al., and US PatentPublication No. 2004/229411 by Battersby.

One published technique offering the potential for a fully self alignedprocess that eliminates the need for complex registration isSelf-Aligned Imprint Lithography (SAIL), as illustrated in U.S. Pat. No.7,056,834 by Mei et al. In imprint lithography, a variable-thicknessresist is prepared on the electronically active layers and a sequencingof chemical etch and materials deposition is matched to controllederosion of the photoresist to produce TFT structures. There aredifficulties with the SAIL process, however. First, robust nanoimprinttechnology is necessary for webs. Second, the SAIL process requires highaccuracy etch depth control, which may not be consistent with a low costprocess. Finally, a significant limitation of the SAIL process is thatlayers produced by the mask cannot be fully independent. As an example,it is particularly challenging to form openings under continuous layerswith this approach, an essential element in a matrix backplane design.

There is also interest in utilizing lower cost processes for materialsdeposition that do not involve the expense associated with vacuumprocessing and subtractive patterning processes. In typical vacuumdepositions, a large metal chamber and sophisticated vacuum pumpingsystems are required in order to provide the necessary environment. Intypical subtractive patterning systems, much of the material depositedin the vacuum chamber is removed, for example in an etch step. Thesedeposition and subtractive patterning methods have high capital costsand preclude the easy use of continuous web-based systems.

It would be desirable to combine materials deposition and patterningemploying selective area deposition, or SAD. As the name implies,selective area deposition involves treating portion(s) of a substratesuch that a material is deposited only in those areas that are desired,or selected. In this approach, a deposition process employing eitherliquid or vapor phase chemical delivery would be tailored to operate ina manner where material selectively deposits only in certain areas.

Atomic layer deposition (“ALD”) is an example of a film depositiontechnology that potentially can be used as a fabrication step forforming a number of types of thin-film electronic devices andcomponents, including semiconductor devices and supporting electroniccomponents such as resistors and capacitors, insulators, bus lines, andother conductive structures. ALD is particularly suited for forming thinlayers of metal oxides in the components of electronic devices. Generalclasses of functional materials that can be deposited with ALD includeconductors, dielectrics or insulators, and semiconductors. One approachto combining patterning and depositing a semiconductor by ALD is shownin U.S. Pat. No. 7,160,819 by Conley, Jr. et al. Conley, Jr. et al.discuss materials for use in patterning Zinc Oxide on silicon wafers. Noinformation is provided on the use of other substrates, or the resultsfor other metal oxides. Sinha et al. (J. Vac. Sci. Technol. B 24 62523-2532 (2006)), have remarked that selective area ALD requires thatdesignated areas of a surface be masked or “protected” to prevent ALDreactions in those selected areas, thus ensuring that the ALD filmnucleates and grows only on the desired unmasked regions. It is alsopossible to have SAD processes where the selected areas of the surfacearea are “activated” or surface modified in such a way that the film isdeposited only on the activated areas.

A number of materials have been used by researchers as directorinhibitor compounds for selective area deposition. Sinha et al.,referenced above, use poly(methyl methacrylate (PMMA) in their maskinglayer. Conley, Jr. et al. employed acetone and deionized water, alongwith other process contaminants as deposition inhibitor materials. Theproblem with these previously used director inhibitors is that they areonly effective to direct selected thin materials. Additionally, in orderto be useful in constructing devices, director inhibitor compounds needto be patterned. Additive methods of patterning director inhibitors,such as lithography or inkjet are limited in their resolution. Also,there remains a difficulty in aligning the different layers in a finaldevice that cannot be resolved by selected area deposition alone.

Therefore, there is a need for a director inhibitor compound that canwork with a range of thin film materials, is easily patterned, and issuited to highly accurate patterning in a simple way. The presentinvention facilitates highly accurate patterning in a simple way, andsolves one or more of the aforesaid problems.

PROBLEM TO BE SOLVED BY THE INVENTION

The problems addressed by the current invention are to reproducepatterned features across large areas while having precise control overthe feature dimensions and the registration and alignment patternedfeatures that are in different layers. Additionally, it is highlydesirable to overcome these problems in a way that does not requireexpensive equipment or expensive processes.

SUMMARY OF THE INVENTION

The invention generally is accomplished by a process for forming astructure comprising:

a) providing a transparent support;

b) forming a color mask, having a color pattern, on a first side of thetransparent support;

c) applying a first layer comprising a deposition inhibitor materialthat is sensitive to visible light either on the first side or a sideopposite the first side of the transparent support after forming thecolor mask;

d) patterning the first layer comprising the deposition inhibitormaterial by exposing the first layer through the color mask with visiblelight to form a first pattern, wherein the first pattern is composed ofdeposition inhibitor material in a second exposed state that isdifferent from a first as-coated state, and developing the depositioninhibitor material to provide selected areas of the first layereffectively not having the deposition inhibitor material; and

e) depositing a second layer of functional material over the transparentsupport;

wherein the second layer of functional material is substantiallydeposited only in selected areas over the transparent support not havingthe deposition inhibitor material.

ADVANTAGEOUS EFFECT OF THE INVENTION

One advantage of the present invention is that it provides a method forforming aligned layers without the need for expensive alignmentequipment and processes. A further advantage of the present invention isthat it provides a method for additive patterning of inorganic thinfilms in a selective area deposition process. There are many potentialadvantages to selective area deposition techniques, such as eliminatingan etch process for film patterning, reducing the number of cleaningsteps required, patterning materials that are difficult to etch, andpatterning layered structures that are difficult to etch selectively.Another advantage is that a multicolor mask can be used to enableautomatic alignment of layers, which multicolor mask can be prepareddirectly on the support in color-encoded form ensuring that the correctmask is used. Additionally, deposition inhibitor materials that arepatterned using a visible light exposure as proposed can be used topattern all layers of a transistor structure directly on a color mask,for example a transistor comprising a transparent oxide semiconductorsuch as materials based on zinc oxide. The multicolor mask has theadvantage of containing more independently addressable levels than agrayscale mask and works particularly well for patterning transparentelectronic materials.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features, and advantages of the presentinvention will become more apparent when taken in conjunction with thefollowing description and schematic drawings wherein identical referencenumerals have been used, where possible, to designate identical oranalogous features that are common to the figures, and wherein:

FIGS. 1 and 1A show a pattern of blue color absorber on a transparentsupport;

FIGS. 2 and 2A show a pattern of green color absorber on a transparentsupport;

FIGS. 3 and 3A show a pattern of red color absorber on a transparentsupport;

FIGS. 4 and 4A show the individual color absorber layers in a layeredstructure on support material forming a multicolor mask;

FIGS. 5A-5D show a process for selectively forming a pattern of materialregistered with the blue color absorber pattern of the multicolor mask;

FIGS. 6A-6D show a process for selectively forming a pattern of materialregistered with the green color absorber pattern of the multicolor mask;

FIGS. 7A-7D show a process for selectively forming a pattern of materialregistered with the red color absorber pattern of the multicolor mask;

FIGS. 8A-8H show a process where three different patterned structuresare selectively formed by changing the color of exposing light throughthe multicolor mask;

FIGS. 9A-9F show an example of a liftoff patterning process using amulticolor mask;

FIGS. 10A-10F show an example of a selective etch patterning processusing a multicolor mask;

FIGS. 11A-11F show a selective deposition patterning process using amulticolor mask;

FIGS. 12A-14H show a possible sequence of exposure, processing, anddeposition steps to form a multilayer electronic device usingtransparent components and a multicolor mask;

FIGS. 15A and 15B illustrate another embodiment of a multicolor mask ofthe present invention; and

FIGS. 16A, 16B and 16C show another embodiment of a layer electronicdevice formed using a multicolor mask of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

For ease of understanding, the following terms used herein are describedbelow in more detail.

As utilized herein, the term “front” as applied to the invention articleis the side of the support carrying the functional patterned layers. Theterm “back” as used herein refers to the side of the support opposite tothe side carrying the patterned functional layers.

“Vertical” means substantially perpendicular to the surface of asubstrate.

“Transparent” generally denotes a material or construct that does notabsorb a substantial amount of light in the visible portion (and/orinfrared portion in certain variants) of the electromagnetic spectrum.In this invention, the transparency of a materials is only withreference to the colors of light that are being used in a particularprocess step. Transparent means at least 65% of the reference lightpasses through the member.

“Photopatternable” refers to a material that, upon exposure to light,changes in states, for example, in terms of solubility, tackiness,mechanical strength, permeability to etchants or gases, surfacereactivity and/or index of refraction, which allows subsequentphotopatterning of the material, for example by development and removalof areas of the applied material based on the photopatterning.

“Positive” refers to a pattern, which contains material in those areasabove the colored parts of the photomask.

“Negative” refers to a pattern, which contains material in those areasabove the transparent parts of the photomask.

“Multicolor mask” refers to the vertically aligned set of colorabsorbing layers in the patterned structure. The color patterns of amulticolor mask may be in separate layers or in the same layer.

A thin film transistor (TFT) is a likely electronic element that canbenefit from the patterning process of this invention. The next threedefinitions refer specifically to thin film transistors.

As used herein, the terms “over,” “above,” and “under” and the like,with respect to layers in the thin film transistor, refer to the orderof the layers with respect to the support, but do not necessarilyindicate that the layers are immediately adjacent or that there are nointermediate layers.

“Gate” generally refers to the insulated gate terminal of a threeterminal FET when used in the context of a transistor circuitconfiguration.

The preceding term descriptions are provided solely to aid the reader,and should not be construed to have a scope less than that understood bya person of ordinary skill in the art or as limiting the scope of theappended claims.

The phrase “deposition inhibitor material” refers herein to the materialapplied to the substrate as well as the material resulting from anyoptionally subsequent crosslinking or other reaction that modifies thematerial that may occur prior to depositing an inorganic thin film onthe substrate. Preferably, a polymeric photopatternable depositioninhibitor material may be crosslinked after applying the polymer ontothe substrate via exposure to visible light.

The process of this invention can be used to generate any variety ofmultilayer structures containing patterned layers with fixed verticalregistration. This process is therefore capable of producingmonolithically integrated structures that can be designed to function asconductors, inductors, capacitors, transistors, diodes, photodiodes,light emitting diodes, and other electronic or optoelectroniccomponents. Furthermore, the patterning technology can be used tosimultaneously produce a number of these devices arranged in a way toproduce useful electronic circuitry.

In one embodiment, accurate pattern overlay over large areas and onflexible supports is enabled by use of a color-encoded mask, amulticolored mask which is prepared directly on the support, incombination with spectrally sensitized photopatternable layers. Thecolor-encoded mask contains either in one structure, or in multipleportions, all or most of the patterning information for the system.Transparent electronic materials are subsequently deposited inlayer-by-layer fashion. Spectrally sensitized photopatternable layersare selectively exposed through the multicolored mask to formphotopatterns on the front side of the support, vertically aligned tothe color mask. Patterning of at least one electrically active layer isaccomplished by using a selective deposition process. If desired, otherphotopatternable layers formed by exposure through the multicolor maskmay be used to pattern electrically active layers using etch or liftoffprocesses. The multicolor mask can be attached to the transparentsupport and can be formed on either side of the support or portionsthereof on both sides of the support. In one embodiment, the mask can beformed only on the same side of the support as the active layers. Themulticolor mask can contain pattern information for all of the layers ina process. Fabrication using the present invention can be fullyself-aligning, and catastrophic overlay errors arising from dimensionalchange of supports, web weave, and transport errors can be avoided.

In one embodiment of the present invention, the entire multicolor maskremains as part of the final device. In another embodiment of theinvention, only a first portion of the multicolor mask remains in thefinal device. These embodiments will be better understood with respectto the figures.

The figures and following description illustrate a masking scheme of thecurrent invention. The illustrative example of this description utilizesthree masking layers, composed of different color absorbing materials,and utilizes photopatternable materials, sensitive to colored light, topattern transparent functional layers. The figures are intended toillustrate the present invention and should not be considered limiting.Multicolor masks of two masking layers, as well as multicolor masks ofgreater than three masking layers are alternative embodiments of thepresent invention.

Light used for exposing can be panchromatic or colored. Panchromaticlight refers to light that has some spectral intensity over the visiblespectrum. Panchromatic light should be recognized by one skilled in theart as light is a light that contains multiple colors. Colored lightgenerally refers to light that has high intensity in certain spectralregions and lower intensities in others. Colored light can be describedby the wavelength of the maximum intensity (λ_(max)) and by the FWHM(full width at half the maximum), or by the bandpass.

As mentioned above, the present process involves applying a first layercomprising a deposition inhibitor material that is sensitive to visiblelight either on the first side or a side opposite the first side of thetransparent support after forming the color mask, patterning the firstlayer by exposing the first layer through a color mask with visiblelight to form a first pattern, developing the deposition inhibitormaterial to provide selected areas of the first layer effectively nothaving the deposition inhibitor material; and then applying a layer offunctional material which is patterned based on the patterned firstlayer. However, this step may be combined with other patterningtechniques for additional layers of functional materials in the overallstructure.

Referring now to the drawings, the embodiments of FIGS. 1-3A show thepatterns of three different mask layers. FIGS. 1 and 1A show the patternof a first mask layer as a pattern of a blue color absorber (14) ontransparent support (12). FIGS. 2 and 2A show the pattern of a secondmask layer as a pattern of a green color absorber (18) on transparentsupport (12). FIGS. 3 and 3A show the pattern of a third mask layer as apattern of a red color absorber (16) on transparent support (12). FIGS.4 and 4A show an article 11 composed of individual color absorber layers(14, 16, 18) in a layered structure on support material formingmulticolor mask (10). An important aspect of this embodiment is that themulticolor mask contains in one structure most or all of the patterninginformation for the system in a color-encoded form. This is importantbecause the entire article, including support (12) may be exposed tovarying temperature, pressure, solvent and humidity treatments duringthe fabrication and coating steps, naturally leading to variations indimension (such as shrinkage or thermal expansion) of the support. Webtransport systems apply tension to the support, leading to dimensionalinstability as well. In fact, the lowest cost and potentially cheapestsupport materials are likely to have a higher degree of dimensionalinstability. For example, polyester film has a thermal expansioncoefficient of 0.0018% per ° C., such that a 5° C. change can result ina dimensional change of 90 μm over 1 meter. The effect of humidityexpansion and thermal expansion need not lead to cumulative andcatastrophic alignment errors when a multicolor mask element (10) isprovided. Simply, the patterning information is contained in the colorabsorbing layers that are attached to the support, and thus remain infixed vertical alignment as the support shrinks or expands and are notimpacted by support dimensional change.

FIGS. 5A-7D show processes for selectively forming patterns ofphotopatternable material registered with a specific color absorberpattern of multicolor mask (10). The specific pattern to be formed isselected by adjusting the sensitivity distribution of thephotopatternable film. A photopatternable layer (22) with a sensitivityto blue, green, or red light is coated on the multicolor mask. Thisphotopatternable layer is exposed with light through the multicolormask.

The color absorbers of the multicolor mask selectively transmit theilluminating light, thereby exposing the photopatternable layer to apattern of colored light. For example, a cyan mask absorbs red lightwhile transmitting blue and green light. Similarly, a magenta maskabsorbs green light while transmitting red and blue light and a yellowmask absorbs blue light while transmitting red and green light. Thus, bycombining the properties of such individual masks, a multicolor mask maybe formed to provide patterns of selectively transmitted light. Thesensitivity distribution of the photopatternable layer, in a preferredembodiment, is completely contained within the absorption spectrum ofone of the color absorbing materials used in multicolor mask (10) andcompletely isolated from the absorption spectrum of the other colorabsorbing materials in multicolor mask (10). In a preferred embodimentof the invention, the photopatternable layer contains a polymerizablecompound and a photoinitiator responsive only to specific wavelengths ofcolored light. Absorption of colored light by the photoinitiatorinitiates the photopolymerization reaction. The photopatternable layermay contain additional components that include but are not limited topolymeric binders, fillers, pigments, surfactants, adhesion modifiers,antioxidants, co-initiators, chain transfer agents, and the like. Oneconvenient way to modify the sensitivity distribution of thephotopatternable layer is with the identity of the photoinitiator. Thespectral distribution of illuminating light may be specifically selectedto minimize effects from unwanted absorption of the color absorbingmaterial and/or unwanted sensitivity of the photopatternable layer.Following exposure, the photopatternable layer is developed. Theremaining pattern may be the positive image of the mask layer or thenegative image of the mask layer, depending on the type ofphotopatternable material used.

FIGS. 5A-7D illustrate the use of a photocurable or negative workingphotopatternable layer. FIGS. 5A-5D show a process for selectivelyforming a pattern of material registered with the blue color absorberpattern of the multicolor mask. Referring now to FIGS. 5A and 5B, thereis illustrated a schematic plan view and cross-sectional view of themulticolor mask (10) that has been coated with a blue photopatternablelayer (22) and exposed with a light source containing blue light. Thislight source may provide white light or panchromatic light. In thisembodiment, the photopatternable material of the photopatternable layeris negative working. FIGS. 5C and 5D show the schematic plan view andcross-sectional view of the resulting structure after the exposedblue-curable film from FIG. 5A has been developed, forming a pattern ofblue-cured material (24) registered with the blue color absorber pattern(14) of multicolor mask (10).

FIGS. 6A-6D show a process for selectively forming a pattern of materialregistered with the green color absorber pattern of the multicolor mask.FIGS. 6A and 6B show a schematic plan view and cross-sectional view ofthe multicolor mask (10) that has been coated with a greenphotopatternable layer (30) and exposed with a light source containinggreen light. Again, in this embodiment, the light source may providewhite light or panchromatic light, and the photopatternable material ofthe photopatternable layer is negative working.

FIGS. 6C and 6D show a schematic plan view and cross-sectional view ofthe resulting structure after the exposed green-curable film from FIG.6A has been developed, forming a pattern of green-cured material (32)registered with the green color absorber pattern (18) of multicolor mask(10).

FIGS. 7A-7D show a process for selectively forming a pattern of materialregistered with the red color absorber pattern of the multicolor mask.FIGS. 7A and 7B show a schematic plan view and cross-sectional view ofthe multicolor mask (10) that has been coated with a red curable film(38) and exposed with a light source containing red light. Again, inthis embodiment, the light source may provide white light orpanchromatic light, and the photopatternable material of thephotopatternable layer is negative working.

FIGS. 7C and 7D show a schematic plan view and cross-sectional view ofthe resulting structure after the exposed red-curable film from FIG. 7Ahas been developed, forming a pattern of red-cured material (40)registered with the red color absorber pattern (16) of multicolor mask(10).

FIGS. 8A-8H show a process where three different patterned structuresare selectively formed by changing the color of exposing light throughthe multicolor mask and employing a film 44 curable with panchromaticlight. A pan-curable film may be formulated, for example, which containsa polymerizable compound and a mixture of red, green, and blueresponsive photoinitiators. When a pan-curable film is used with thepresent process, the specific pattern to be formed is selected byadjusting the spectral energy distribution of the exposing light.Therefore, the absorption spectrum of the color absorbing material forthe intended pattern should match the wavelength of exposing light.

FIGS. 8A-8H also serve to illustrate another embodiment of the presentinvention. Multicolor mask 10 may optionally have a transparent coating50 on the top surface. The transparent coating 50 may have insulating,smoothing, planarizing or other properties which improve the performanceof the end device that will be formed over the multicolor mask 10. FIGS.8A-8H illustrate the present invention using negative actingphotopatternable materials; one skilled in the art will understand thatthe present invention may also be used with positive acting materials.FIGS. 8A and 8B show a schematic plan view and cross-sectional view ofthe multicolor mask (10), which has been coated with a filmphotopatternable with panchromatic light (44).

FIGS. 8C and 8D show a schematic plan view and cross-sectional view ofthe resulting structure after the film photopatternable withpanchromatic light (44) from FIG. 8A has been exposed with blue lightand developed, forming a pattern of cured pan-photopatternable material(46) registered with the blue color absorber pattern (14) of multicolormask (10).

FIGS. 8E and 8F show a schematic plan view and cross-sectional view ofthe resulting structure after the film photopatternable withpanchromatic light (44) from FIG. 8A has been exposed with green lightand developed, forming a pattern of cured pan-photopatternable material(46) registered with the green color absorber pattern (18) of multicolormask (10).

FIGS. 8G and 8H show a schematic plan view and cross-sectional view ofthe resulting structure after the film photopatternable withpanchromatic light (44) from FIG. 8Aa has been exposed with red lightand developed, forming a pattern of cured pan-photopatternable material(46) registered with the red color absorber pattern (16) of multicolormask (10). It will be readily understood that combinations of patternsshown in FIGS. 8C-8H are possible simply by tuning the color of exposinglight (i.e. a blue-plus-green light exposure will cure both shadedregions (46) shown in FIGS. 8C and 8E).

An important aspect of a preferred embodiment of the process is theability to use one of the color patterns of the multicolor mask to forman aligned pattern of a functional material on at least a portion of themulticolor mask. A number of methods can be used to cause thispatterning. Therefore, both functional materials and photopatternablematerials are applied to the multicolor mask and patterned using coloredlight. General classes of functional materials that can be used includeconductors, dielectrics or insulators, and semiconductors. The spectraldistribution of illuminating light is modulated by the transmittance ofall previously applied and patterned layers. For the purposes of thisdiscussion, the multicolor mask (10) is defined as including all colorabsorbing portions of the patterned structure with the exception of thelight curable film. Because the colored light photopatterning processdescribed above and illustrated using FIGS. 5A-8H results in a change inpermeability, solubility, tackiness, mechanical strength, surfacereactivity, or index of refraction of the photopatterned material, theseproperties may be exploited in subsequent fabrication steps.Particularly useful methods to pattern functional and electronicmaterials are referred to as liftoff, selective etch, and selectivedeposition processes.

FIGS. 9A-9F show a liftoff patterning process. FIGS. 9A and 9B show aschematic plan view and cross-sectional view of the multicolor mask (10)with a pattern of photopatterned material (46) registered with greencolor absorber pattern (18). Referring now to FIGS. 9C and 9D, a uniformcoating of transparent functional material (48) is applied over thepattern of photopatterned material (46). FIGS. 9D and 9E show the finalstep in a liftoff sequence when the cured material (46) and portions oftransparent functional material on top of the cured material areremoved. This is accomplished, for example, by treating the sample witha material that selectively attacks the remaining cured material underthe functional material. This leaves functional material where there wasoriginally no photopatterned material.

FIG. 10A-10F show a selective etch patterning process. FIGS. 10A and 10Bshow a schematic plan view and cross-sectional view of multicolor mask(10) with a uniform coating of transparent functional material (48)under a pattern of cured material (46) registered with green colorabsorber pattern (18). FIGS. 10C and 10D illustrate a subsequent stepafter the exposed portions of transparent functional material areremoved in an etch process. The sample is exposed to a material thatattacks or dissolves the functional layer. Regions of transparentfunctional material protected by the pattern of cured material (46) arenot removed in the etch step. The pattern of transparent functionalmaterial (48) is registered with the pattern of cured material (46) andis also registered with green color absorber pattern (18). Referring nowto FIGS. 10E and 10F there is illustrated the resulting structure afterthe pattern of cured material (46) is removed. This may be accomplished,for example, with a compatible solvent or oxygen plasma treatment.

A number of deposition processes employing both liquids and vapor phasechemical delivery can be tailored to operate in a manner where materialselectively deposits only in certain areas. Compared to etch and liftoffpatterning processes, selective area deposition processes areparticularly attractive for building structured materials. This isbecause they can eliminate the need for an etch process for filmpatterning and reduce the number of cleaning steps required. They canalso allow the patterning of materials difficult to etch or thepatterning of layered structures which are difficult to etchselectively. For all these reasons, it is a goal of the present processto provide a patterned thin film that not only comprises depositioninhibitor material, but that is directly photopatternable using amulticolor mask.

As described above, SAD processes use a deposition inhibitor compound inorder to inhibit the deposition of the thin film in the non-selectedareas. This process can be better understood with reference to FIGS.11A-11F, which show the operation of this system using a selectivedeposition patterning process in combination with the multicolor mask.

FIGS. 11A and 11B show multicolor mask (10) with a pattern of curedmaterial (46) registered with green color absorber pattern (18). FIGS.11C and 11D illustrate a subsequent step after a transparent functionalmaterial (48) is selectively deposited on regions of support (12) thatare not covered by the pattern of cured material (46). Referring now toFIGS. 11E and 11F a subsequent step is illustrated where the pattern ofcured material (46) is removed by treating entire to attack theremaining cured material. The pattern of transparent functional material(48) is registered with the green color absorber pattern (18).

FIGS. 12A-14H show a possible sequence of exposure, processing, anddeposition steps that would allow construction of a multilayerelectronic device as seen in FIGS. 14G and 14H.

FIGS. 12A-12H illustrate the coating and patterning steps for the firsttransparent layer of a electronic device using a blue photopatternablecoating and a selective etch process. Alternatively, the firsttransparent layer could be patterned by a selective deposition process,a liftoff process, or a light curing process. FIGS. 12A and 12B showmulticolor mask (10) coated with a first transparent functional material(20) and a blue photopatternable material (22). This structure isexposed with a light source containing blue light. By way ofillustration, the functional material (20) could be a transparentconducting oxide material such as ITO or aluminum doped ZnO. Because thephotopatternable coating (22) drawn in this structure is sensitive onlyto blue light, the light source may provide white light source or acolored light containing blue light. Referring now to FIGS. 12C and 12Dthere is illustrated the resulting structure after the exposed bluephotopatternable film has been developed, forming a pattern of bluecured material (24) registered with the blue color absorber pattern (14)of multicolor mask (10). FIGS. 12E and 12F show an etch step whereexposed portions of transparent functional material (20) are removed in,for example, an acid bath, forming a pattern of transparent functionalmaterial (26) registered to the blue color absorber pattern (14) ofmulticolor mask (10). FIGS. 12G and 12H show the structure of FIG. 12Eafter the pattern of blue cured material (24) is removed using, forexample, an oxygen plasma treatment.

FIGS. 13A-13H illustrate the coating and patterning steps for the secondtransparent layer of the electronic device using a green curable coatingusing a selective etch process. Alternatively, the second transparentlayer could be patterned be a selective deposition process, a liftoffprocess, or a light curing process. FIGS. 13A and 13B show themulticolor mask (10), including the first patterned transparent layer,coated with a uniform layer of transparent functional material (28) anda green photopatternable layer (30). This structure is exposed with alight source containing green light. By way of example, the transparentfunctional material (28) could be a dielectric material such as aluminumoxide or alternatively a semiconducting layer such as zinc oxide. Thismaterial could be a dielectric or semiconducting layer precursor that isconverted in an annealing step to form the electrically functionalmaterial. Multiple layers of transparent functional layers couldpotentially be coated at this step. By way of example, a transparentcoating of a dielectric material could be first applied and a secondtransparent coating of semiconductor material could be subsequentlyapplied. Because the photopatternable coating (30) shown in FIGS. 13Aand 13B is sensitive only to green light, the light source may providewhite light or colored light containing green light. FIGS. 13C and 13Cshow the resulting structure after the exposed green photopatternablematerial (30) from FIG. 30 has been developed, forming a pattern ofgreen-cured material (32) registered with the green color absorberpattern (18) of multicolor mask (10).

Referring now to FIGS. 13E and 13F there is illustrated the structure ofFIG. 13C after the exposed portions of transparent functional material(28) are removed in an etch step, forming a pattern of transparentfunctional material (34) registered to the green color absorber pattern(18) of multicolor mask (10). FIGS. 13G and 13H show the structure ofFIG. 13E after the pattern of green cured material (32) is removedusing, for example, an oxygen plasma treatment.

FIGS. 14A-14H illustrate the coating and patterning steps for the thirdtransparent layer of the electronic device using a red curable coatingusing a selective etch process. Alternatively, the third layer could bepatterned using a selective deposition process, a liftoff process, or alight curing process. FIGS. 14A and 14B show the multicolor mask (10),including the first and second patterned transparent layers, coated witha uniform layer of transparent functional material (36) and ared-photopatternable material (38). This structure is exposed with alight source containing red light. By way of example, the transparentfunctional material (36) could be a layer of indium-tin oxide or silvernanoparticles. Because the photopatternable coating (38) drawn in thisstructure is sensitive only to red light, the light source may providewhite light or a colored light source containing red light.

FIGS. 14C and 14D show the resulting structure after the exposedred-photopatternable material (38) from FIG. 14A has been developed,forming a pattern of red-cured material (40) registered with the redcolor absorber pattern (16) of multicolor mask (10).

Referring now to FIGS. 14E and 14F there is illustrated the structure ofFIG. 14C after the exposed portions of transparent functional material(36) are removed in an etch step, forming a pattern of transparentfunctional material (42) registered to the red color absorber pattern(16) of multicolor mask (10). FIGS. 14G and 14H show the structure ofFIG. 14E after the pattern of red cured material (40) is removed. Inthis multilayer structure, the pattern of transparent functionalmaterial (26) is registered to the blue color absorber pattern (14) ofmulticolor mask (10). The pattern of transparent functional material(34) is registered to the green color absorber pattern (18) ofmulticolor mask (10). The pattern of transparent functional material(42) is registered to the red color absorber pattern (16) of multicolormask (10).

FIGS. 15A and 15B illustrate alternative arrangements of multicolor mask10 according to the present invention. In these embodiments, multicolormask 10 is made up of a first mask portion 120 formed on the first sideof substrate and a second mask portion 122 formed on the backside of thesubstrate. This alternative arrangement has the advantage of allowingfor the removal of a portion of the multicolor mask. The first maskportion 120 will remain in the final device, while the second maskportion 122 may be removed after completion of the final device. Thismay particularly useful in display devices that are viewed through thetransparent substrate. The use of these alternative multicolor maskstructures should be easily understood with respect to the previousFigs.

FIGS. 16A and 16B are analogous to FIGS. 14G and 14H, and illustrate acompleted device formed using a multicolor mask with a first maskportion 120 formed on the first side of substrate and a second maskportion 122 formed on the backside of the substrate. FIG. 16Cillustrates the completed device after the additional step of removingthe second mask portion.

An important aspect of the present process is the multicolor mask cancontain in one structure most or all of the patterning information forthe system. This multicolor mask can be generated by any method thatproduces an image containing the desired colors with sufficientprecision and registration for the anticipated application.

The different color absorbers in the multicolor mask may be sequentiallyor simultaneously deposited and patterned by many methods. One method toproduce the multicolor mask is to print the mask using inks containingdyes or pigments with the appropriate spectral qualities. Inks used inthe printing could be of any common formulation, which would typicallyinclude the colorant material along with a vehicle or solvent, binders,and surfactants. Examples of such multicolor printing systems are inkjetprinting, gravure printing, flexography, offset lithography, screen orstencil printing, and relief printing. Color thermographic printing maybe used to produce the different color absorbing layers on the support.Thermochromic compounds, bleachable dyes, heat decomposable compounds,or chemical color formers may be used to form the different colorabsorbing layer patterns on the support. The different color absorbersmay be applied to the support using a laser or thermal transfer processfrom a donor sheet. Alternately, the color absorbing patterns may beproduced on the support by an ablative recording process.

Particularly useful color absorbers are those materials with maximumabsorption in a selected portion of the visible band and maximumtransmission in remaining portions. So-called block-type dyes and cutofffilter materials are ideal for use in the multicolor mask. The differentcolor absorbers may be applied in any convenient order, or applied in asingle layer dispersed in a binder. A receiving layer for colorabsorbing materials may optionally be coated on the back side of thesupport before the color absorbing materials are applied.

The different color absorbers in the multicolor mask may be formed by aphotolithographic method using, for example, dyed photocurable coatings,such as pigmented or dyed photoresist.

It may be particularly convenient and cost effective to produce areusable master image for subsequent duplication on the main substrate.In this embodiment, a master mask image is produced of very highaccuracy and resolution. This may be accomplished with any of the abovetechniques. Preferably, this would be done with a photolithographicmethod that allows a very high quality master image to be produced. Itmay even be preferable to produce the master image upon a rigidtransparent substrate in order to achieve highly accurate verticalalignment between color absorbing layers. The color information in themaster color image can be reproduced on the main substrate using a colorduplicating or color copying process. For negative-working duplicationprocesses, the master color image would be provided as a negative copyof the multicolor mask.

In a traditional photolithographic process for large area electronicdevice fabrication, excellent alignment must be achieved over very largeareas. In the above method of master duplication, the master may beconsiderably smaller and thus easier to fabricate, but then duplicatedon the final substrate in a replicating pattern so as to cover a largerarea. Although this method of stepping is used for individual masklayers in a conventional photolithographic process, in those processesexcellent alignment is still required within the stepping operation. Inthe current inventive process, considerable tolerance can exist in thelocation of the individual duplications, since each will contain all therequired information for a multilayer pattern.

Color image capture processes employing light sensitive materials may beused to reproduce the master color image. The light sensitive layers canbe composed of any set of materials capable of capturing a multicolorlight pattern and subsequently being treated or developed in a way toproduce a color pattern. Examples of such multicolor image capturematerials are color negative photographic imaging layers, color reversalphotographic imaging layers, color photothermographic imaging layers,Cycolor imaging layers, and diffusion transfer color photographicimaging layers such as color instant films, and color Pictrography film.A master color image may alternatively be reproduced on the mainsubstrate using a color duplicating or copying process such as colorelectrophotography.

A multicolor mask can be produced on a separate roll of material andthen laminated to the substrate. Preferably the lamination is done withthe image side of the mask opposite the substrate and that the maskimage is as close as possible to the functional layers to be patterned.For embodiments with a portion of the mask on the back side of thesubstrate, the lamination should be done such that the mask image is asclose to the substrate as possible.

It may be particularly advantageous for optical considerations to coatthe main support layer directly onto the color absorbing layers of themulticolor mask. In this embodiment, the color absorbing layers could bepatterned on a carrier support roll and then the main support layercould be cast directly onto the color absorbing layers.

Alternately, the color absorbing layers can be patterned on a separate(donor) roll of material and then all of the color absorbing layers canbe transferred in a single step from the donor roll onto the mainsubstrate.

Multicolor mask layers may be separated from electronically activelayers by a barrier layer. Depending on the application, it may bepreferable to place the color layers on the back of a thin support sothey may be bleached or removed at the end of the fabrication processand will not create planarity and contamination problems for the activedevice layers. As noted above, having a portion of the multicolor maskon the device side of the substrate and a portion on the backside, forpotential removal, is advantageous for some devices.

In view of the above, it is useful to understand the resolution limitfor a remotely exposed photoresist layer. This type of exposure isreferred to as a proximity exposure in traditional photolithography. Inproximity mode, the mask does not contact the wafer, so there areresolution losses due to diffraction effects. A useful discussion ofresolution in this so-called proximity printing mode can be found in“Photoreactive Polymers: The Science and Technology of Resists” by A.Reiser, Wiley-Interscience, John Wiley & Sons, 1989, pp. 234-246.

The diffraction effect in proximity printing limits the minimum featuregap on the mask as described by Equation (1):W_(min)≈√{square root over (kλS)} k≈1  Equation (1)where W_(min), is the minimum feature gap on the mask, λ is the exposurewavelength, and S is the separation between the mask and the wafer.Similarly, the minimum line/gap period is given by the relationship:

$\begin{matrix}{{2b_{\min}} = {3\sqrt{\lambda\left( {s + \frac{z}{2}} \right)}}} & {{Equation}\mspace{14mu}(2)}\end{matrix}$where b_(min) is the minimum line gap period, λ is the exposurewavelength, s is the separation between the mask and the wafer, and z isthe resist thickness.

These models indicate that even for a 100 μm typical for flexiblesupports, 6-8 μm features are resolvable, depending on the exposurewavelength. Again at the 100 μm distance, a line/gap periodicity in therange 9-12 μm should be resolvable, depending on the exposurewavelength. In the case of front-side masking, the barrier thickness isalso highly tunable. Table A uses Equations (1) and (2) to predict theminimum feature size and periodicity as a function of the mask andresist separation. Examples using 365 nm or 650 nm exposing light areshown as representative of the two ends of the visible spectrum.

TABLE A Exposing Mask and resist layer separation wavelength 1 um 10 um100 um (nm) separation separation separation Wmin minimum 365 0.6 2 6resolvable gap (μm) 650 0.8 2.5 8 bmin minimum 365 1.1 3 9 resolvable650 1.5 4 12 periodicity (μm)

Based on these models, the multicolor mask can be designed to meet theresolution and transparency requirements of the final device.

Many polymers can be caused to vary their properties by exposure tolight and, thus, be useful as photopatternable layers, either as aphotopatternable deposition inhibitor material or as photoresist forother patterning techniques not involving SAD. Photopatternablematerials useful in the present invention are those which cause selectedarea deposition, which will be better understood from the discussionbelow. Many typical light sensitive polymers are only sensitive to UVand deep UV radiation. Preferably the photopatternable materials forthis invention are rendered sensitive to visible light.

The phrase “deposition inhibitor material” refers herein to the materialapplied to the substrate as well as the material resulting from anyoptionally subsequent crosslinking or other reaction that modifies thematerial that may occur prior to depositing a functional material on thesubstrate. Preferably, a polymeric photosensitive deposition inhibitormaterial can be crosslinked after applying the polymer onto thesubstrate via exposure to visible light.

A photopatternable deposition inhibitor material can comprise a compoundor polymer that, after being applied, is subsequently polymerized and/orcrosslinked. Polymers are preferably addition polymers such as, forexample, a poly(perfluoroalkyl methacrylate); poly(perfluoroalkylmethacrylate); poly(methyl methacrylate); poly(cyclohexyl methacrylate);poly(benzyl methacrylate); poly(iso-butylene);poly(9,9-dioctylfluorenyl-2,7-diyl); polystyrene; poly(vinyl alcohol);poly(methyl methacrylate); poly(hexafluorobutyl methacrylate), andcopolymers thereof, wherein the alkyl has one to six carbon atoms. Thedeposition inhibitor materials preferably have an inhibition power; inwhich the inhibition power is defined as the functional layer thicknessat or below which the deposition inhibitor material is effective, of atleast 50 Å, more preferably at least 100 Å, most preferably at least 300Å.

Crosslinking can be used to insolubilize a polymeric depositioninhibitor material after application onto the surface of the substrate.The crosslinking can occur prior to patterning or may occur duringpatterning in order to contribute to the patterning step, for example,by employing crosslinking initiated by, and patterned by, exposing thephotopatternable deposition inhibitor through the multicolor mask,followed by removal of non-crosslinked polymer, for example, by solvent.

For use in a photoresist or photopatternable deposition inhibitormaterial, a variety of photopolymerization systems that are activated byvisible radiation have been developed. A useful discussion of UV curableand visible light photopatternable materials can be found in“Photoreactive Polymers: The Science and Technology of Resists” by A.Reiser, Wiley-Interscience, John Wiley & Sons, 1989, pp. 102-129. U.S.Pat. No. 4,859,572 by Farid et al., incorporated here by reference,describes a photographic imaging system, which relies on using visiblelight to harden an organic component and produce an image pattern. Thisreference describes a variety of suitable visible light sensitivephotoinitiators, monomers, and film formulation guidelines for use inthe curable layers of this process.

Sensitivity to visible light can be accomplished by the use ofpolymerizable compound along with a photopolymerization initiator. In apreferred embodiment of the invention, a photoresist and/orphotopatternable deposition inhibitor contains a polymerizable compoundselected from among compounds having at least one, preferably two ormore, ethylenically unsaturated bond at terminals. Such compounds arewell known in the industry and they can be used in the present inventionwith no particular limitation. Such compounds have, for example, thechemical form of a monomer, a prepolymer, i.e., a dimer, a trimer, andan oligomer or a mixture and a copolymer of them. As examples ofmonomers and copolymers thereof, unsaturated carboxylic acids (e.g.,acrylic acid, methacrylic acid, itaconic acid; crotonic acid,isocrotonic acid, maleic acid, etc.), and esters and amides thereof canbe exemplified, and preferably esters of unsaturated carboxylic acidsand aliphatic polyhydric alcohol compounds, and amides of unsaturatedcarboxylic acids and aliphatic polyhydric amine compounds are used. Inaddition, the addition reaction products of unsaturated carboxylicesters and amides having a nucleophilic substituent such as a hydroxylgroup, an amino group and a mercapto group with monofunctional orpolyfunctional isocyanates and epoxies, and the dehydration condensationreaction products of these compounds with monofunctional orpolyfunctional carboxylic acids are also preferably used. The additionreaction products of unsaturated carboxylic esters and amides havingelectrophilic substituents such as an isocyanato group and an epoxygroup with monofunctional or polyfunctional alcohols, amines and thiols,and the substitution reaction products of unsaturated carboxylic estersand amides having releasable substituents such as a halogen group and atosyloxy group with monofunctional or polyfunctional alcohols, aminesand thiols are also preferably used. As another example, it is alsopossible to use compounds replaced with unsaturated phosphonic acid,styrene, vinyl ether, etc., in place of the above-unsaturated carboxylicacids.

Specific examples of ester monomers of aliphatic polyhydric alcoholcompounds and unsaturated carboxylic acids include, as acrylates,ethylene glycol diacrylate, triethylene glycol diacrylate,1,3-butanediol diacrylate, tetramethylene glycol diacrylate, propyleneglycol diacrylate, neopentyl glycol diacrylate, trimethylolpropanetriacrylate, trimethylolpropane tri(acryloyloxypropyl)ether,trimethylolethane triacrylate, hexanediol diacrylate,1,4-cyclohexanediol diacrylate, tetraethylene glycol diacrylate,pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritoltetraacrylate, dipentaerythritol diacrylate, dipentaerythritolhexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitolpentaacrylate, sorbitol hexaacrylate, tri(acryloyloxyethyl)isocyanurate,polyester acrylate oligomer, etc. As methacrylates, examples includetetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate,neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate,trimethylolethane trimethacrylate, ethylene glycol dimethacrylate,1,3-butanediol dimethacrylate, hexanediol dimethacrylate,pentaerythritol dimethacrylate, pentaerythritol trimethacrylate,pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate,dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitoltetramethacrylate, andbis[p-(3-methacryloxy-2-hydroxy-propoxy)phenyl]dimethylmethane,bis[p-(methacryloxyethoxy)-phenyl]dimethylmethane. As itaconates,examples include ethylene glycol diitaconate, propylene glycoldiitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate,tetramethylene glycol diitaconate, pentaerythritol diitaconate, andsorbitol tetraitaconate. As crotonates, examples include ethylene glycoldicrotonate, tetramethylene glycol dicrotonate, pentaerythritoldicrotonate, and sorbitol tetradicrotonate. As isocrotonates, examplesinclude ethylene glycol diisocrotonate, pentaerythritol diisocrotonate,and sorbitol tetraisocrotonate. As maleates, examples include ethyleneglycol dimaleate, triethylene glycol dimaleate, pentaerythritoldimaleate, and sorbitol tetramaleate. Further, the mixtures of theabove-described ester monomers can also be used. Further, specificexamples of amide monomers of aliphatic polyhydric amine compounds andunsaturated carboxylic acids include methylenebis acrylamide,methylenebis-methacrylamide, 1,6-hexamethylenebis-acrylamide,1,6-hexamethylenebis-methacrylamide, diethylenetriaminetris-acrylamide,xylylenebis-acrylamide, and xylylenebis-methacrylamide.

Further, urethane-based addition polymerizable compounds which areobtained by the addition reaction of an isocyanate and a hydroxyl groupcan also be used in the present process in a photoresist orphotopatternable deposition inhibitor. A specific example is a vinylurethane compound having two or more polymerizable vinyl groups in onemolecule, which is obtained by the addition of a vinyl monomer having ahydroxyl group represented by the following formula (V) to apolyisocyanate compound having two or more isocyanate groups in onemolecule.CH₂═C(R)COOCH₂CH(R′)OHwherein R and R′ each represents H or CH₃.

Other examples include polyfunctional acrylates and methacrylates, suchas polyester acrylates, and epoxy acrylates obtained by reacting epoxyresins with (meth)acrylic acids. Moreover, photo-curable monomers andoligomers listed in Sartomer Product Catalog by Sartomer Company Inc.(1999) can be used as well.

Depending upon the final design characteristics of the photosensitivematerial, a suitable addition polymerizable compound or combination ofaddition polymerizable compounds, having the desired structure andamounts can be used. For example, the conditions are selected from thefollowing viewpoint. For the photosensitive speed, a structurecontaining many unsaturated groups per molecule is preferred and in manycases bifunctional or more functional groups are preferred. Forincreasing the strength of an image part, i.e., a cured film,trifunctional or more functional groups are preferred. It is effectiveto use different functional numbers and different polymerizable groups(e.g., acrylate, methacrylate, styrene compounds, vinyl ether compounds)in combination to control both photosensitivity and strength. Compoundshaving a large molecular weight or compounds having high hydrophobicityare excellent in photosensitive speed and film strength, but may not bepreferred from the point of development speed and precipitation in adeveloping solution. The selection and usage of the additionpolymerizable compound are important factors for compatibility withother components (e.g., a binder polymer, an initiator, a functionalmaterial, etc., as the case may be) in the photopolymerizationcomposition. For example, sometimes compatibility can be improved byusing a low purity compound or two or more compounds in combination.Further, it is also possible to select a compound having specificstructure for the purpose of improving an adhesion property. Concerningthe compounding ratio of the addition polymerizable compound in aphotopolymerization composition, the higher the amount, the higher thesensitivity. But, too large an amount sometimes may result indisadvantageous phase separation, problems in the manufacturing processdue to the stickiness of the photopolymerization composition (e.g.,manufacturing failure resulting from the transfer and adhesion of thephotosensitive material components), and precipitation from a developingsolution. The addition polymerizable compound may be used alone or incombination of two or more. In addition, appropriate structure,compounding ratio and addition amount of the addition polymerizablecompound can be arbitrarily selected taking into consideration thedegree of polymerization hindrance due to oxygen, resolving power,fogging characteristic, refractive index variation and surface adhesion.

Organic polymeric binders which can optionally form a part of the filmforming component of a photopatternable layer include: (1) polyesters,including those based on terephthalic, isophthalic, sebacic, adipic, andhexahydroterephthalic acids; (2) nylons or polyamides; (3) celluloseethers and esters; (4) polyaldehydes; (5) high molecular weight ethyleneoxide polymers—e.g., poly(ethylene glycols), having average weightaverage molecular weights from 4000 to 4,000,000; (6) polyurethanes; (7)polycarbonates; (8) synthetic rubbers—e.g., homopolymers and copolymersof butadienes; and (9) homopolymers and copolymers formed from monomerscontaining ethylenic unsaturation such as polymerized forms of any ofthe various ethylenically unsaturated monomers, such aspolyalkylenes—e.g. polyethylene and polypropylene; poly(vinyl alcohol);polystyrene; poly(acrylic and methacrylic acids and esters)—e.g.poly(methyl methacrylate) and poly(ethyl acrylate), as well as copolymervariants. The polymerizable compound and the polymeric binder can beemployed together in widely varying proportions, including polymerizablecompound ranging from 3 to 97 percent by weight of the film formingcomponent and polymeric binder ranging from 97 to 3 percent by weight ofthe film forming component. A separate polymeric binder, althoughpreferred, is not an essential part of the photopatternable film and ismost commonly omitted when the polymerizable compound is itself apolymer.

Various photoinitiators can be selected for use in the above-describedimaging systems. Preferred photoinitators consist of an organic dye.

The amount of organic dye to be used is preferably in the range of from0.1 to 5% by weight based on the total weight of the photopolymerizationcomposition, preferably from 0.2 to 3% by weight.

The organic dyes for use as photoinitiators in the present invention maybe suitably selected from conventionally known compounds having amaximum absorption wavelength falling within a range of 300 to 1000 nm.High sensitivity can be achieved by selecting a desired dye having anabsorption spectrum that overlaps with the absorption spectrum of thecorresponding color absorbing material of the multicolor mask describedabove and, optionally, adjusting the absorption spectrum to match thelight source to be used. Also, it is possible to suitably select a lightsource such as blue, green, or red, or infrared LED (light emittingdiode), solid state laser, OLED (organic light emitting diode) or laser,or the like for use in image-wise exposure to light.

Specific examples of the photoinitiator organic dyes include3-ketocoumarin compounds, thiopyrylium salts, naphthothiazolemerocyaninecompounds, merocyanine compounds, and merocyanine dyes containingthiobarbituric acid, hemioxanole dyes, and cyanine, hemicyanine, andmerocyanine dyes having indolenine nuclei. Other examples of the organicdyes include the dyes described in Chemistry of Functional Dyes (1981,CMC Publishing Co., Ltd., pp. 393-416) and Coloring Materials (60 [4],212-224, 1987). Specific examples of these organic dyes include cationicmethine dyes, cationic carbonium dyes, cationic quinoimine dyes,cationic indoline dyes, and cationic styryl dyes. Examples of theabove-mentioned dyes include keto dyes such as coumarin dyes (includingketocoumarin and sulfonocoumarin), merostyryl dyes, oxonol dyes, andhemioxonol dyes; nonketo dyes such as nonketopolymethine dyes,triarylmethane dyes, xanthene dyes, anthracene dyes, rhodamine dyes,acridine dyes, aniline dyes, and azo dyes; nonketopolymethine dyes suchas azomethine dyes, cyanine dyes, carbocyanine dyes, dicarbocyaninedyes, tricarbocyanine dyes, hemicyanine dyes, and styryl dyes;quinoneimine dyes such as azine dyes, oxazine dyes, thiazine dyes,quinoline dyes, and thiazole dyes.

Preferably, the photoinitiator organic dye is a cationic dye-borateanion complex formed from a cationic dye and an anionic organic borate.The cationic dye absorbs light having a maximum absorption wavelengthfalling within a range from 300 to 1000 nm and the anionic borate hasfour R groups, of which three R groups each represents an aryl groupwhich may have a substitute, and one R group is an alkyl group, or asubstituted alkyl group. Such cationic dye-borate anion complexes havebeen disclosed in U.S. Pat. Nos. 5,112,752; 5,100,755; 5,057,393;4,865,942; 4,842,980; 4,800,149; 4,772,530; and 4,772,541, which areincorporated herein by reference.

When the cationic dye-borate anion complex is used as the organic dye inthe photopolymerization compositions of the invention, it does notrequire to use the organoborate salt. However, to increase thephotopolymerization sensitivity, it is preferred to use an organoboratesalt in combination with the cationic dye-borate complex. The organicdye can be used singly or in combination.

Specific examples of the above-mentioned cationic dye-borate salts aregiven below. However, it should be noted that the present invention isnot limited to these examples.

It may be preferable to use the photoinitiator in combination with anorganic borate salt such as disclosed in U.S. Pat. Nos. 5,112,752;5,100,755; 5,057,393; 4,865,942; 4,842,980; 4,800,149; 4,772,530; and4,772,541. If used, the amount of borate compound contained in thephotopolymerization composition of the invention is preferably from 0%to 20% by weight based on the total amount of photopolymerizationcomposition. The borate salt useful for the photosensitive compositionof the present invention is represented by the following general formula(I).[BR₄]⁻Z⁺where Z represents a group capable of forming cation and is not lightsensitive, and [BR4]⁻ is a borate compound having four R groups whichare selected from an alkyl group, a substituted alkyl group, an arylgroup, a substituted aryl group, an aralkyl group, a substituted aralkylgroup, an alkaryl group, a substituted alkaryl group, an alkenyl group,a substituted alkenyl group, an alkynyl group, a substituted alkynylgroup, an alicyclic group, a substituted alicyclic group, a heterocyclicgroup, a substituted heterocyclic group, and a derivative thereof.Plural Rs may be the same as or different from each other. In addition,two or more of these groups may join together directly or via asubstituent and form a boron-containing heterocycle. Z+ does not absorblight and represents an alkali metal, quaternary ammonium, pyridinium,quinolinium, diazonium, morpholinium, tetrazolium, acridinium,phosphonium, sulfonium, oxosulfonium, iodonium, S, P, Cu, Ag, Hg, Pd,Fe, Co, Sn, Mo, Cr, Ni, As, or Se.

Specific examples of the above-mentioned borate salts are given below.However, it should be noted that the present invention is not limited tothese examples.

Various additives can be used together with the photoinitiator system toaffect the polymerization rate. For example, a reducing agent such as anoxygen scavenger or a chain-transfer aid of an active hydrogen donor, orother compound can be used to accelerate the polymerization. An oxygenscavenger is also known as an autoxidizer and is capable of consumingoxygen in a free radical chain process. Examples of useful autoxidizersare N,N-dialkylanilines. Examples of preferred N,N-dialkylanilines aredialkylanilines substituted in one or more of the ortho-, meta-, orpara-position by the following groups: methyl, ethyl, isopropyl,t-butyl, 3,4-tetramethylene, phenyl, trifluoromethyl, acetyl,ethoxycarbonyl, carboxy, carboxylate, trimethylsilymethyl,trimethylsilyl, triethylsilyl, trimethylgermanyl, triethylgermanyl,trimethylstannyl, triethylstannyl, n-butoxy, n-pentyloxy, phenoxy,hydroxy, acetyl-oxy, methylthio, ethylthio, isopropylthio,thio-(mercapto-), acetylthio, fluoro, chloro, bromo and iodo.Representative examples of N,N-dialkylanilines useful in the presentinvention are 4-cyano-N,N-dimethylaniline, 4-acetyl-N,N-dimethylaniline,4-bromo-N,N-dimethylaniline, ethyl 4-(N,N-dimethylamino)benzoate,3-chloro-N,N-dimethylaniline, 4-chloro-N,N-dimethylaniline,3-ethoxy-N,N-dimethylaniline, 4-fluoro-N,N-dimethylaniline,4-methyl-N,N-dimethylaniline, 4-ethoxy-N,N-dimethylaniline,N,N-dimethylaniline, N,N-dimethylthioanicidine4-amino-N,N-dimethylaniline, 3-hydroxy-N,N-dimethylaniline,N,N,N′,N′-tetramethyl-1,4-dianiline, 4-acetamido-N,N-dimethylaniline,2,6-diisopropyl-N,N-dimethylaniline (DIDMA),2,6-diethyl-N,N-dimethylaniline, N,N,2,4,6-pentamethylaniline (PMA) andp-t-butyl-N,N-dimethylaniline.

It may be preferable to use the photoinitiator in combination with adisulfide coinitiator. Examples of useful disulfides are described inU.S. Pat. No. 5,230,982 by Davis et al., which is incorporated herein byreference. Two of the most preferred disulfides aremercaptobenzothiazo-2-yl disulfide and 6-ethoxymercaptobenzothiazol-2-yldisulfide. In addition, thiols, thioketones, trihalomethyl compounds,lophine dimer compounds, iodonium salts, sulfonium salts, azinium salts,organic peroxides, and azides, are examples of compunds useful aspolymerization accelerators.

Other additives which can be incorporated into the photopatternablecoatings, either a photoresist or photopatternable deposition inhibitorused in making various structures according to the present process,include polymeric binders, fillers, pigments, surfactants, adhesionmodifiers, and the like. To facilitate coating on the support andfunctional layers the photopatternable film composition is usuallydispersed in a solvent to create a solution or slurry, and then theliquid is evaporatively removed, usually with heating, after coating.Any solvent can be employed for this purpose which is inert toward thefilm forming components and addenda of the photopatternable film.

It may be preferable to practice the invention with positive-workingphotopatternable materials. By way of example, U.S. Pat. No. 4,708,925by Newman (hereby incorporated by reference) describes apositive-working photopatternable composition containing novolakphenolic resins, an onium salt, and a dye sensitizer. In this system,there is an interaction between alkali-soluble phenolic resins and oniumsalts which results in an alkali solvent resistance when it is cast intoa film. Photolytic decomposition of the onium salt restores solubilityto the resin. Unlike the quinine diazides which can only be poorlysensitized, if at all, onium salts can be readily sensitized to a widerange of the electromagnetic spectrum from UV to infrared (280 to 1100nm).

Examples of compounds which are known to sensitize onium salts are thosein the following classes: diphenylmethane including substituteddiphenylmethane, xanthene, acridine, methine and polymethine (includingoxonol, cyanine, and merocyanine) dye, thiazole, thiazine, azine,aminoketone, porphyrin, colored aromatic polycyclic hydrocarbon,p-substituted aminostyryl compound, aminotriazyl methane, polyarylene,polyarylpolyene, 2,5-diphenylisobenzofuran, 2,5-diarylcyclopentadiene,diarylfuran, diarylthiofuran, diarylpyrrole, polyaryl-phenylene,coumarin and polyaryl-2-pyrazoline. The addition of a sensitizer to thesystem renders it sensitive to any radiation falling within theabsorption spectrum of the said sensitizer. Other positive-workingsystems are known to those skilled in the art.

In one embodiment, the deposition inhibitor material comprises anorganosiloxane polymer. The organosiloxanes are defined generically toinclude compounds substantially comprising, within their chemicalstructure, a skeleton or moiety made up of alternate Si and O atoms, inwhich at least one, preferably two organic groups are attached to the Siatom on either side of the —O—Si—O— repeat units. The organic groups canhave various substituents such as halogens, including fluorine. Mostpreferably the organic groups are independently substituted orunsubstituted alkyl, phenyl, or cycloalkyl groups having 1 to 6 carbonatoms, preferably 1 to 3 carbon atoms, preferably substituted orunsubstituted methyl.

Organosiloxane polymers are defined to include polymers, prepolymers, ormacromonomers having at least 20 siloxane repeat units. Particularlypreferred are deposition inhibitor materials that, after applicationonto the substrate, and any crosslinking or intermolecular reaction, areinsoluble. Such organosiloxane polymers include random or block and/orcrosslinked polymers.

Optionally, functional groups may be present on the organosiloxanepolymer such as terminal groups (also referred to as endcaps).Crosslinking groups, and/or functional groups may also be present, forexample, located on a side chain off a siloxane backbone.

Examples of organosiloxane polymers include, for example,poly(alkylsiloxane), poly(arylsiloxane), poly(alkylarylsiloxane), andpoly(alkyl(aryl)siloxane), optionally having functional groups. Suchfunctionalized poly(siloxanes) include epoxy-functionalized,carboxyl-functionalized, polyether-functionalized,phenol-functionalized, amino-functionalized, alkoxy-functionalized,methacryl-functionalized, carbinol-functionalized,hydroxy-functionalized, vinyl-functionalized, acrylic-functionalized,silane-functionalized, trifluoro-functionalized, ormercapto-functionalized poly(organosiloxanes). Block copolymers can alsobe employed if containing substantial siloxane repeat units. Suchpolymers can be prepared as described in numerous patents andpublications or are commercially available from, for example, GeneralElectric, Dow Corning, and Petrarch.

The preferred poly(organosiloxane) polymers, including random or blockcopolymers, comprise organic groups (attached to the silicon atoms) thatare independently hydrogen, alkyl having from 1 to 18 carbons, such asmethyl, ethyl, propyl, butyl, and the like; an aryl group having 6 to 18carbons, preferably 6 to 8 carbon atoms, such as phenyl, benzyl,napthyl, and the like; a mercaptoalkyl group having from 1 to 18carbons, such as mercaptopropyl; an aminoalkyl group having from 1 to 18carbons, such as aminopropyl or aminoisopropyl; trifluoroalkyl having 1to 18 carbons, such as trifluoromethyl; or trifluoroaryl having 6 to 18carbons, such as trifluoromethylphenyl. The preferred weight averagemolecular weight range for the poly(organosiloxane) polymers, if notcrosslinked, is 200 to 140,000, more preferably 4,000 to 120,000.Preferably, alkyl groups have 1 to 6 carbon atoms, more preferably 1 to3 carbon atoms. A particularly preferred organosiloxane polymercomprises a vinyl terminated siloxane that is crosslinked.

Mixtures of organosiloxanes with a photopolymerizable matrix activatedby visible radiation are preferable compositions for use in the presentinvention. Blends of organosiloxanes with cyclized rubber (polycis-isoprene), a bis-azide (such as2,6-bis(4-azidobenzal)-4-methylcyclohexanone) and a photosensitizer, areparticularly preferred photopatternable compositions for use with thepresent invention, particularly when combined with an ALD selectivedeposition step. The sensitization of poly cis-isoprene resists tovisible wavelengths has been described, for example, by J. Frejlich andR. Knoesel (Applied Optics, 18 8 1135-1136 (1979), using tripletsensitizers such as 9-fluorenone. In a preferred embodiment of thepresent invention, it is preferable to include an organosiloxane withthe photopolymerizable composition forming a photopatternable depositioninhibitor.

Once a photopatternable deposition inhibitor layer is exposed, it can bedeveloped by any means known the art. Development is the process bywhich the soluble portions of photopatternable deposition inhibitorlayer are removed. Methods for developing typically include exposure toa selective solvent, heating, or combinations thereof. A liquiddeveloper can be any convenient liquid which is capable of selectivelyremoving the photopatternable layer based on exposure level. The exposedphotopatternable layer can be sprayed, flushed, swabbed, soaked,sonicated, or otherwise treated to achieve selective removal. In itssimplest form the liquid developer can be the same liquid employed as asolvent in coating the light curable film. In some instances thephotoresist is not rendered soluble where it is ultimately to beremoved, but is instead rendered susceptible to a particular reactionthat occurs during exposure to a development solution which then permitssolubility.

In patterning processes where the photopatterned deposition inhibitorlayer film is not intended to be part of the final article, it needs tobe removed after it has been used to successfully pattern an area. Thisremoval can be accomplished with any means known in the art, includedplasma treatments, especially plasmas including oxygen, solvent basedstripping, and mechanical or adhesive means.

In many embodiments the photopatternable layer is simply a layer used topattern another functional layer. However, circumstances may exist inwhich the light cured layer is also the functional layer. Examples ofthis are the use of a curable layer as a dielectric due to itsinsulating behavior, or as a structural element such as a small wall ormicrocell due to its mechanical properties. This use of photopatternablelayers as functional layers is not limited to the above examples.

In the process for the article of this invention there is required alight source that emits light of some spectrum, the multicolor mask thatcontains at least two color records in which each is capable ofabsorbing light of some spectrum, and a photopatternable layer that iscapable of responding to light of some spectrum.

The system can function in several modes:

(1) White light, defined as light of a very broad visible spectrum, canbe used as the illumination source. In this case, it is required thatthe photopatternable layer have a sensitivity distribution thatsubstantially matches the absorption spectrum of the target color recordof the color mask. Substantially matching spectrum is defined as theintegrated product of the two spectra, each normalized to an area of 1,exceeding 0.5, preferably exceeding 0.75, most preferably exceeding 0.9.

(2) Colored light, as defined by light of a narrow spectrum, can be usedas the illumination source. In this case, the absorption spectrum ofphotopatternable layer can be made to substantially match the spectrumof the emitted light, or the absorption spectrum can be broad. Theformer case may be desirable for improved sensitivity of thephotopatternable layer and reduced cross talk between layers, while thelatter case may be desirable for allowing several process steps toemploy a single photopatternable layer formulation.

In some cases it may be desirable to apply a black layer to part of themulticolor mask. Such a black layer has the property of absorbingsubstantially all of the light in those areas of the mask having theblack layer. If, for example, large areas of the final product aredesired to have no patterning, a black printed mask can be used in thoseareas.

In much of the preceding discussion the color mask is referred to ashaving color absorption corresponding to the traditional observablecolors of the visible spectrum. However, this applies a limitation tothe number of individual mask levels that can be accomplished with thisapproach. In principle a high number of individual color records can beused provided that each color record can be independently addressed inthe process. In addition, by utilizing infrared and ultraviolet portionsof the spectrum, the number of mask levels may further be increased. Itis envisioned that upwards of 6 individual mask levels can be achievedwith the current invention.

In this process, light passes through the multicolor mask and thenthrough the previously applied functional layers on the front of thesubstrate. As a result, the light must pass through the previouslyapplied layers with weak enough modulation as to not overly affect theresulting images formed on the applied light curable layers. Therequirement for transparency of the applied functional layers is thuslimited to having an acceptably low effect on the curable layer imagingprocess. In principle therefore, the previously applied can absorb lightuniformly as long as this absorption is low, preferably having anoptical density of less than 0.5. Furthermore, the materials can absorbvery strongly but only in regions where the imaging chemistry is notbeing used, or where these spectral ranges have been used but in priorstages of the manufacture of the article. Furthermore, the final layerin the process can be of any opacity, since additional patterning is notrequired on top.

An aspect of this invention is the ability to at will use one of thecolors of the multicolor mask to form a pattern on the front side of theitem by the direction light through the substrate to cause an effect. Anumber of methods can be used to cause the patterning.

(a) A functional material can be coated uniformly over the multicolormask of the item and then overcoated with a photopatternable resistmaterial that hardens when it is exposed to light through the substrate.The hardened material is then more difficult to remove, so in asubsequent development step, the photopatternable resist is patterned tohave openings where no light has struck. The item can then be exposed toa material that attacks the functional layer, thus removing it where nolight has struck. This is a negative etch process. FIGS. 9A-9Fillustrate how a multicolor mask is used in a negative etch patterningsequence.

(b) A functional material can be coated uniformly upon over themulticolor mask of the item and then overcoated with a photopatternableresist material that softens when it is exposed to light from the backside. The softened materials is then easier to remove, so in asubsequent development step, the resist is patterned to have openingswhere light has struck. The item can then be exposed to a material thatattacks the functional layer, thus removing it where light has struck.This is a positive etch process. FIGS. 10A-10F illustrate how amulticolor mask is used in a positive etch patterning sequence.

(c) A photopatternable resist material can be coated followed byexposure and development step as outlined in (a) or (b). This will yielda resist pattern that has holes in it. This can then be overcoated witha uniform layer of a functional material. If the entire item is thentreated with a material that attacks the remaining photoresist under thefunctional material, it can remove material where photoresist resides.This will leave functional material where there was originally nophotoresist. This is a liftoff process. FIGS. 11A-11F illustrate how amulticolor mask is used in a liftoff patterning process.

(d) A number of deposition processes employing both liquids and vaporphase chemical delivery can be tailored to operate in a manner wherematerial selectively deposits only in certain areas. For example, aphotopatternable resist material can be coated followed by exposure anddevelopment step as outlined in (a) or (b). Next, a deposition processthat leads to material being deposited only in those regions where noresist material remains. The entire item is then treated with a materialor process that attacks the remaining resist. The material or processmay remove the remaining resist or leave it in a benign form for futureprocess steps. This is selective deposition. FIG. 12A-12H illustrate howa multicolor mask can be used in the present invention using a selectivedeposition patterning process.

A support can be used for supporting the device during manufacturing,testing, and/or use. As used in this disclosure, the terms “support” and“substrate” may be used interchangeably. The skilled artisan willappreciate that a support selected for commercial embodiments may bedifferent from one selected for testing or screening variousembodiments. In some embodiments, the support does not provide anynecessary electrical function for the device. This type of support istermed a “non-participating support” in this document. Useful materialscan include organic or inorganic materials. For example, the support maycomprise inorganic glasses, ceramic foils, polymeric materials, filledpolymeric materials, acrylics, epoxies, polyamides, polycarbonates,polyimides, polyketones,poly(oxy-1,4-phenyleneoxy-1,4-phenylenecarbonyl-1,4-phenylene)(sometimes referred to as poly(ether ether ketone) or PEEK),polynorbornenes, polyphenyleneoxides, poly(ethylenenaphthalenedicarboxylate) (PEN), poly(ethylene terephthalate) (PET),poly(ether sulfone) (PES), poly(phenylene sulfide) (PPS), andfiber-reinforced plastics (FRP).

A flexible support is used in some embodiments. This allows forroll-to-roll or roll-to-sheet processing, which may be continuous,providing economy of scale and economy of manufacturing over flat and/orrigid supports. The flexible support chosen preferably is capable ofwrapping around the circumference of a cylinder of less than about 50 cmdiameter, more preferably 25 cm diameter, most preferably 10 cmdiameter, without distorting or breaking, using low force as by unaidedhands. The preferred flexible support may be rolled upon itself.

If flexibility is not a concern, then the substrate may be a wafer orsheet made of materials including glass as well as any other transparentmaterial.

The thickness of the substrate may vary, and according to particularexamples it can range from about 10 μm to about 1 mm. Preferably, thethickness of the substrate is in the range from about 10 μm to about 300μm. Provided the exposing light source is sufficiently collimated tolimit the angular spread of light through the support layer, eventhicker substrates can be tolerated. Particularly for embodiments wherea portion of the multicolor mask is on the back side of the support, itmay be advantageous, for optical considerations, to coat or cast themain support layer directly onto the color absorbing layers of thesecond portion of the multicolor mask. In some embodiments, such asupport is optional, particularly when a support layer is a functionallayer or a color absorbing layer of the multicolor mask.

In addition, the multicolor mask and support may be combined with atemporary support. In such an embodiment, a support may be detachablyadhered or mechanically affixed to the multicolor mask.

Any material that can form a film on the substrate can be patterned withthis invention, as long as the appropriate etching and or depositionconditions are chosen. General classes of functional materials that canbe used include conductors, dielectrics or insulators, andsemiconductors. Functional materials of the present invention may bedeposited in using any convenient method. Typical deposition processesinclude chemical vapor deposition, sputtering, evaporation, thermaltransfer or solution processing. One embodiment of the currentinvention, the functional materials are applied using gravure or inkjet.In another embodiment the functional material is deposited using AtomicLayer Deposition (ALD). In a preferred embodiment of the presentinvention, the functional material is deposited by an ALD systemconsisting of a gas distribution manifold having a plurality of openingsthrough which first and second reactive gases flow as the manifold andthe substrate move relative to each other. Co-pending, commonly assignedUS Patent Publication No. 2007/0238311 describes such a method in detailand the disclosure of which is hereby incorporated in its entirety byreference.

Conductors as functional materials can be any useful conductivematerial. A variety of conductor materials known in the art, are alsosuitable, including metals, degenerately doped semiconductors,conducting polymers, and printable materials such as carbon ink,silver-epoxy, or sinterable metal nanoparticle suspensions. For example,the conductor may comprise doped silicon, or a metal, such as aluminum,chromium, gold, silver, nickel, copper, tungsten, palladium, platinum,tantalum, and titanium. Conductors can also include transparentconductors such as indium-tin oxide (ITO), ZnO, SnO₂, or In₂O₃.Conductive polymers also can be used, for example polyaniline,poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) (PEDOT:PSS). Inaddition, alloys, combinations, and multilayers of these materials maybe most useful.

The thickness of the conductor may vary, and according to particularexamples it can range from about 5 to about 1000 nm. The conductor maybe introduced into the structure by chemical vapor deposition,sputtering, evaporation and/or doping, or solution processing.

A dielectric electrically insulates various portions of a patternedcircuit. A dielectric layer may also be referred to as an insulator orinsulating layer. The dielectric should have a suitable dielectricconstant that can vary widely depending on the particular device andcircumstance of use. For example, a dielectric constant from about 2 to100 or even higher is known for a gate dielectric. Useful materials fora dielectric may comprise, for example, an inorganic electricallyinsulating material. Specific examples of materials useful for the gatedielectric include strontiates, tantalates, titanates, zirconates,aluminum oxides, silicon oxides, tantalum oxides, titanium oxides,silicon nitrides, barium titanate, barium strontium titanate, bariumzirconate titanate, zinc selenide, and zinc sulfide. In addition,alloys, combinations, and multilayers of these examples can be used as adielectric. Of these materials, aluminum oxides, silicon oxides, andsilicon nitride are useful. The dielectric may comprise a polymericmaterial, such as polyvinylidenedifluoride (PVDF), cyanocelluloses,polyimides, polyvinyl alcohol, poly(4-vinylphenol), polystyrene andsubstituted derivatives thereof, poly(vinyl naphthalene) and substitutedderivatives, and poly(methyl methacrylate) and other insulators having asuitable dielectric constant. The gate electric may comprise a pluralityof layers of different materials having different dielectric constants.

The thickness of a dielectric layer may vary, and according toparticular examples it can range from about 15 to about 1000 nm. Thedielectric layer may be introduced into the structure by techniques suchas chemical vapor deposition, sputtering, atomic layer deposition,evaporation, or a solution process.

Semiconductors used in this system may be organic or inorganic.Inorganic semiconductors include classes of materials exhibitingcovalently bonded lattices, and may also include amorphous materialswhere the lattice exhibits only short range order. Examples of usefulsemiconducting materials are single elements such as silicon orgermanium, and compound semiconductors such as gallium arsenide, galliumnitride, cadmium sulfide, and zinc oxide. Useful organic semiconductorsinclude linear acenes such as pentacenes, naphthalenediimides such asthose described in co-pending patent applications, perylenediimides,polythiophenes, polyfluorenes.

In typical applications of a thin film transistor, the desire is for aswitch that can control the flow of current through the device. As such,it is desired that when the switch is turned on a high current can flowthrough the device. The extent of current flow is related to thesemiconductor charge carrier mobility. When the device is turned off, itis desired that the current flow be very small. This is related to thecharge carrier concentration. Furthermore, it is desired that the devicebe weakly or not at all influenced by visible light. In order for thisto be true, the semiconductor band gap must be sufficiently large (>3eV) so that exposure to visible light does not cause an inter-bandtransition. A material that is capable of yielding a high mobility, lowcarrier concentration, and high band gap is ZnO.

The entire process of making the thin film transistor or electronicdevice of the present invention, or at least the production of the thinfilm semiconductor, is preferably carried out below a maximum supporttemperature of about 200° C., more preferably below 150° C., mostpreferably below about 140° C., and even more preferably below about100° C., or even at temperatures around room temperature (about 25° C.to 70° C.). The temperature selection generally depends on the supportand processing parameters known in the art, once one is armed with theknowledge of the present invention contained herein. These temperaturesare well below traditional integrated circuit and semiconductorprocessing temperatures, which enables the use of any of a variety ofrelatively inexpensive supports, such as flexible polymeric supports andthe multicolor mask. Thus, the invention enables production ofrelatively inexpensive circuits containing thin film transistors.

Electronically or optically active layers may be formed and doped usingsolution processes, vacuum vapor deposition techniques, or atmosphericvapor deposition processes such as those described in co-pending PatentPublication Nos. 2007/0228470 and 2007/0238311.

The patterning methods of this invention are preferably used to createelectrically and optically active components that are integrated on asubstrate of choice. Circuit components can comprise transistors,resistors, capacitors, conductors, inductors, diodes, and any otherelectronics components that can be constructed by selecting theappropriate patterning and materials. Optically functional componentscan comprise waveguides, lenses, splitters, diffusers, brightnessenhancing films, and other optical circuitry. Structural components cancomprise wells, selective patterns of fillers and sealants, patternedbarrier layers, walls and spacers.

Electronic devices in which TFTs and other devices are useful include,for example, more complex circuits, e.g., shift registers, integratedcircuits, logic circuits, smart cards, memory devices, radio-frequencyidentification tags, backplanes for active matrix displays,active-matrix displays (e.g. liquid crystal or OLED), solar cells, ringoscillators, and complementary circuits, such as inverter circuits, forexample, in which a combination of n-type and p-type transistors areused. In an active matrix displays, a transistor made according to thepresent invention can be used as part of voltage hold circuitry of apixel of the display. In such devices, the TFTs are operativelyconnected by means known in the art.

One example of a microelectronic device is an active-matrixliquid-crystal display (AMLCD). One such device is an optoelectronicdisplay that includes elements having electrodes and an electro-opticalmaterial disposed between the electrodes. A connection electrode of thetransparent transistor may be connected to an electrode of the displayelement, while the switching element and the display element overlap oneanother at least partly. An optoelectronic display element is hereunderstood to be a display element whose optical properties change underthe influence of an electrical quantity such as current or voltage suchas, for example, an element usually referred to as liquid crystaldisplay (LCD). The presently detailed transistor has sufficient currentcarrying capacity for switching the display element at such a highfrequency that the use of the transistor as a switching element in aliquid crystal display is possible. The display element acts inelectrical terms as a capacitor that is charged or discharged by theaccompanying transistor. The optoelectronic display device may includemany display elements each with its own transistor, for example,arranged in a matrix. Certain active matrix pixel designs, especiallythose supplying a display effect that is current driven, may requireseveral transistors and other electrical components in the pixelcircuit.

EXAMPLES

The following non-limiting examples further describe the practice of theinstant invention.

A. Visible Light Curable Film Components

The following materials and coating solutions were used to prepare thevisible light curable films. Stock solution CF-1 contained two grams ofpolymethylmethacrylate (PMMA) (MW ˜75K), 6.5 g of trimethylolpropanetriacrylate, and 20 g of anisole. Stock solution CF-2 contained 1.5grams of ethoxylated trimethylolpropane triacrylate (SR9035 purchasedfrom Sartomer Company, Inc.) and 1.5 g of polyethylene glycol diacrylate(SR610 purchased from Sartomer Company, Inc.) in 4 g of ethanol. Stocksolution CF-3 was a commercial resist CT2000L supplied by FujiPhotochemicals containing a methacrylate derivative copolymer andpolyfunctional acrylate resin in a mixture of2-propanol-1-methoxyacetate and 1-ethoxy-2-propanol acetate. Stocksolution CF-4 contained 1.25 g of a Novolak resin, and 0.2 g of Irgacure250 (purchased from CIBA Specialty Chemicals), in MEK. Stock solutionCF-5 was a positive-working commercial resist SC-1827, (purchased fromRohm and Haas Electronic Materials). Stock solution CF-6 was prepared asfollows.

DEHESIVE 944 is a vinyl-terminated dimethylsiloxane polymer supplied byWacker Chemie AG. Crosslinker V24 is a methylhydrogenpolysiloxanesupplied by Wacker. Catalyst OL is an organoplatinum complex inpolydimethylsiloxane, also supplied by Wacker. Crosslinker V24 andCatalyst OL are used for additional curing of vinyl-terminated siloxanepolymers such as DEHESIVE 944. Stock solution CF-6 was prepared whichcontained 3.3 g of a 1% solution of polymethylmethacrylate dissolved intoluene, 0.5 g of a 10% solution of TMPTA in toluene, 0.25 g of a 0.1%solution of Photoinitiator A in anisole, 0.5 g of a solution containing1.08% DEHESIVE 944, 0.002% Crosslinker V24, and 0.06% Catalyst OL in amixture of 33 parts toluene and 48 parts heptane, and 0.85 g of toluene.Stock solution CF-7 was prepared as follows. A dehesive solution wasprepared containing 0.108% DEHESIVE 944, 0.0002% Crosslinker V24, and0.006% Catalyst OL in a mixture of 33 parts toluene and 48 partsheptane. Stock solution CF-7 contained 1.25 g of HNR-80, 23.75 g oftoluene, and 0.5 g of the dehesive solution.

The stock solutions CF1-CF4 were sensitized to visible light by additionof a dye photoinitiator. Photoinitiator structures appear in Table 1.Photoinitiator solutions were prepared as follows. YPI-1 was a 1%solution of yellow photoinitiator A in anisole. YPI-2 was a 1% solutionof yellow photoinitiator A in ethanol. YPI-3 was a 1% solution of yellowphotoinitiator A in cyclohexanone. MPI-1 was a 1% solution of magentaphotoinitiator B in anisole. MPI-2 was a 1% solution of magentaphotoinitiator B in ethanol. MPI-3 was a 1% solution of magentaphotoinitiator in cyclohexanone. CPI-1 was a 1% solution of cyanphotoinitiator C in anisole. CPI-2 was a 1% solution of photoinitiator Cin ethanol. CPI-3 was a 1% solution of photoinitiator C incyclohexanone.

Stock solution CF-7 was sensitized to visible light by addition ofspectral sensitizing solution F-1. Spectral sensitizer solution F-1 wasa 1% solution of spectral sensitizer 9-fluorenone dissolved in xylene.

Developer solution D-1 was MIBK. Developer solution D-2 was ethanol.Developer solution D-3 was an aqueous solution containing 0.002 Mtetramethylammonium hydroxide and 0.002 M diethanolamine. Developersolution D-4 was Microposit™ MF™-319, purchased from Rohm and HaasElectronic Materials. Developer solution D-5 was WNRD, obtained fromFujifilm Electronic Materials.

TABLE 1 Dye λmax Photoinitiator A

450 nm Photoinitiator B

555 nm Photoinitiator C

645 nmB. Electronic Materials Deposition and Patterning

The following solutions were used to etch the functional materials. E-1was a 50/50 mixture of HCl and water. E-2 was Microposit™ MF™-319Developer purchased from Rohm and Haas Electronic Materials. Subbinglayer S-1 was a 7.5% solution of polycyanoacrylate in a 50/50 mixture ofacetonitrile and cyclopentanone. S-2 was Omnicoat™, purchased fromMicroChem.

C. Electrical Characterization of Transistor Structures

Electrical characterization of the fabricated devices was performed witha Hewlett Packard HP 4156® parameter analyzer. Device testing was donein air in a dark enclosure.

The results were averaged from several devices. For each device, thedrain current (Id) was measured as a function of source-drain voltage(Vd) for various values of gate voltage (Vg). Furthermore, for eachdevice the drain current was measured as a function of gate voltage forvarious values of source-drain voltage. Vg was swept from minus 10 V to40 V for each of the drain voltages measured, typically 5 V, 20 V, and35 V, and 50 V. Mobility measurements were taken from the 35V sweep.

Parameters extracted from the data include field-effect mobility (μ),threshold voltage (Vth), subthreshold slope (S), and the ratio ofIon/Ioff for the measured drain current. The field-effect mobility wasextracted in the saturation region, where Vd>Vg−Vth. In this region, thedrain current is given by the equation (see Sze in SemiconductorDevices—Physics and Technology, John Wiley & Sons (1981)):

$I_{d} = {\frac{W}{2L}\mu\;{C_{ox}\left( {V_{g} - V_{th}} \right)}^{2}}$where, W and L are the channel width and length, respectively, andC_(ox) is the capacitance of the oxide layer, which is a function ofoxide thickness and dielectric constant of the material. Given thisequation, the saturation field-effect mobility was extracted from astraight-line fit to the linear portion of the √I_(d) versus Vg curve.The threshold voltage, V_(th), is the x-intercept of this straight-linefit.

Example 1 Multicolor Mask Formed by Direct Printing Process

In this example, a multicolor mask was prepared containing three colorabsorbing layers, with each color corresponding to an individualfunctional layer of an array of thin film transistor devices. The designfor the gate layer of the array of thin film transistor devices wasconverted into a black and white bitmap file. The design for thesemiconductor layer of the array of thin film transistor devices wasconverted into another black and white bitmap file. The design for thesource and drain layer of the array of thin film transistor device wasconverted into a third black and white bitmap file. These bitmaps werethen imported into the blue channel, green channel, and red channel of asingle color image file using Photoshop 6.0. In this full color image,the blue channel contained the gate layer design as a yellow pattern.The green channel contained the semiconductor layer design as a magentapattern. The red channel contained the source and drain design as a cyanpattern. This color image was printed onto a transparent support using aKodak Professional 8670 Thermal Printer loaded with Kodak ProfessionalEktatherm XLS transparency media. The resulting multicolor mask waslaminated to the nonconductive side of a flexible ITO film purchasedfrom Bekaert Specialty films.

Example 2 Multicolor Mask Formed by Photolithography Process

In this example, a multicolor mask was prepared containing three colorabsorbing layers, with each color corresponding to an individualfunctional layer of an array of thin film transistor devices. Chrome onglass masks for the gate layer (CG-1), semiconductor and dielectriclayers (CG-2), and source and drain layers (CG-3) of the array of thinfilm transistor devices were obtained from Applied Image Incorporated. A0.7 mm thick borosilicate glass support was washed for 10 minutes bytreating with a solution of 70% sulfuric acid and 30% of a 30% solutionof hydrogen peroxide maintained at approximately 100° C. After washing,the clean glass was spin coated (at 1000 RPM) with Color Mosaic SC3200L(purchased from Fujifilm Electronic Materials Co., Ltd.). SC-3200L is aUV curable photoresist containing 3-5% of a cyan pigment, 7-9% of amethacrylate derivative copolymer, 7-9% of a polyfunctional acrylateresin and a UV photosensitizer dispersed in a mixture of propyleneglycol monomethyl ether acetate and ethyl-3-ethoxy-propionate.

The coated glass slide was baked for 1 minute at 95° C., and exposed for1 minute to a pattern of UV light using a 200 W Mercury-Xenon lamp, withmask CG-3 (contact exposure). The cyan photoresist layer was developedfor one minute with a solution of 0.03 M tetramethylammoniumhydroxide/0.03 M diethanolamine in water, rinsed with water, and bakedfor 5 minutes at 200° C.

The sample was then spin coated (at 1000 RPM) with Color Mosaic SM3000L(purchased from Fujifilm Electronic Materials Co., Ltd.). SM-3000L is aUV curable photoresist containing 4-6% of a magenta pigment, 6-8% of amethacrylate derivative copolymer, 6-8% of a polyfunctional acrylateresin and a UV photosensitizer dispersed in a mixture of propyleneglycol monomethyl ether acetate and ethyl-3-ethoxy-propionate. Thecoated glass slide was baked for 1 minute at 95° C., and exposed for 1minute to a pattern of UV light using a 200W Mercury-Xenon lamp, withmask CG-2 (contact exposure). The magenta photoresist layer wasdeveloped for one minute with a solution of 0.03 M tetramethylammoniumhydroxide/0.03 M diethanolamine in water, rinsed with water, and bakedfor 5 minutes at 200° C. The resulting glass substrate contained anarray of registered cyan and magenta patterns. The sample was then spincoated (at 1000 RPM) with Color Mosaic SY3000L, (purchased from FujifilmElectronic Materials Co., Ltd.). SY-3000L is a UV curable photoresistcontaining 3-5% of a yellow pigment, 7-9% of a methacrylate derivativecopolymer, 7-9% of a polyfunctional acrylate resin and a UVphotosensitizer dispersed in a mixture of propylene glycol monomethylether acetate and ethyl-3-ethoxy-propionate. The coated glass slide wasbaked for 1 minute at 95° C., and exposed for 1 minute to a pattern ofUV light using a 200 W Mercury-Xenon lamp, with mask CG-1 (contactexposure). The yellow photoresist layer was developed for one minutewith a solution of 0.03 M tetramethylammonium hydroxide/0.03 Mdiethanolamine in water, rinsed with water, rinsed with water, and bakedfor 5 minutes at 200° C. The resulting multicolor mask contained anarray of registered cyan, magenta, and yellow patterns.

Example 3 Blue-Curable Film Formulation

A coating solution C-1 for the blue light curable film was prepared asfollows. A solution of blue sensitive photoinitiator was prepared byadding 0.03 g of photoinitiator A to 3 grams of toluene.

Photoinitiator A:

In a separate vial, five grams of polymethylmethacrylate (PMMA) (MW˜75K) were dissolved in 45 g of anisole. To 2.9 g of the resulting PMMAsolution, 0.95 g of trimethylolpropane triacrylate and 0.5 g of thesolution of photoinitiator A were added.

Green-Curable Film Formulation:

A coating solution C-2 for the green light curable film was prepared asfollows. A solution of green sensitive photoinitiator was prepared byadding 0.03 g of photoinitiator B to 3 grams of anisole. In a separatevial, five grams of PMMA (MW ˜75K) were dissolved in 45 g of anisole. To2.9 g of the resulting PMMA solution, 0.95 g of trimethylolpropanetriacrylate and 0.5 g of the solution of photoinitiator B were added.

Photoinitiator B:

Example 4 Red-Curable Film Formulation

A coating solution C-3 for the red light curable film was prepared asfollows. A solution of red sensitive photoinitiator was prepared byadding 0.025 g of photoinitiator C to 2.5 grams of anisole. In aseparate vial, five grams of PMMA (MW ˜75K) were dissolved in 45 g ofanisole. To 2.9 g of the resulting PMMA solution, 0.95 g oftrimethylolpropane triacrylate and 0.5 g of the solution ofphotoinitiator C were added.

Photoinitiator C:

Example 5 Registered Conductive Layer Patterns on Flexible Film withSingle Multicolor Mask

The multicolor mask resulting from Example 1 was laminated to thenonconductive side of a flexible ITO film purchased from BekaertSpecialty films. The conductive side was coated with blue-curablecoating solution C-1 by spin coating at a rate of 1000 RPM. The samplewas baked for 1 minute at 80° C., and loaded in a glass cell purged withnitrogen. The sample was illuminated for ⅛″ using a 300 W GE MiniMulti-Mirror FHS projection lamp in such fashion that illuminating lightpasses through the multicolor mask before reaching the blue-curablecoating. Uncured portions of the blue-curable coating were removed bydeveloping for 30 seconds in methylisobutylketone (MIBK). These stepsresulted in formation of a patterned polymer film in registry with theyellow pattern on the color-encoded mask. The ITO layer was etched inHCl:H₂O (1:1) to remove portions of the ITO not covered by theblue-light cured film. Portions of the ITO protected by the pattern ofblue-light cured film remained, resulting in a patterned ITO layer and apatterned polymer film in registry with the yellow pattern on themulticolor mask. The sample was then spin coated with solution of silvernanoparticles and annealed at 110° C. The resulting semitransparentconductive film had a neutral density of 0.6. The silver nanoparticulatelayer was coated with red-curable coating solution C-3 by spin coatingat a rate of 1000 RPM. The sample was baked for 1 minute at 80° C. andexposed for 2″ using the exposure method previously described. Thesample was illuminated for 2″ in such fashion that illuminating lightpassed through the multicolor mask, flexible film, patterned ITO layer,and silver nanoparticle layer before reaching the red-curable coating.Unexposed portions of the red-curable coating were removed by developingfor 30 seconds in MIBK. These steps resulted in formation of a patternedpolymer film in registry with the cyan pattern on the color-encodedmask. The silver layer was etched for 30 seconds using Kodak EktacolorRA-4 bleach-fix solution to produce a patterned silver conductive filmand a patterned red-cured polymer film in registry with the cyan patternof the multicolor mask, a patterned blue-cured polymer film and apatterned ITO conductive film in registry with the yellow pattern of themulticolor mask.

Example 6 Thin Film Transistor

In this example, thin film transistors were prepared using a multicolormask to pattern transparent electronic materials.

The first step in fabricating the transistors was to prepare themulticolor mask in the identical fashion described in Example 1. Thismask was laminated to the nonconductive side of a piece of ITO glass.The conductive side was coated with blue-curable coating solution C-1 byspin coating at a rate of 1000 RPM. The sample was baked for 1 minute at80° C., and loaded in a glass cell purged with nitrogen. The sample wasilluminated for ⅛″ using a 300 W GE Mini Multi-Mirror FHS projectionlamp in such fashion that illuminating light passes through themulticolor mask before reaching the blue-curable coating. Uncuredportions of the blue-curable coating were removed by developing for 30seconds in MIBK. These steps resulted in formation of a patternedpolymer film in registry with the yellow pattern on the color-encodedmask, forming a series of stripes. The ITO layer was etched for 7minutes in HCl:H2O (1:1) to remove portions of the ITO not covered bythe blue-light cured film, forming a series of conducting gate lines.Portions of the ITO protected by the pattern of blue-light cured filmremained, resulting in a patterned ITO layer and a patterned polymerfilm in registry with the yellow pattern on the multicolor mask. Themask layers were removed and an aluminum oxide film was deposited on thepatterned ITO layer using a CVD process with trimethylaluminum and wateras reactive materials entrained in a nitrogen carrier gas. Subsequently,a zinc oxide film was deposited using a CVD process and utilizingdiethyl zinc and water as reactive materials entrained in a nitrogencarrier gas. To facilitate electrical contact to the ITO gate lines, thealuminum oxide and zinc oxide films did not cover the top 5 mm of thesample area. Metal source and drain contacts were deposited using vacuumevaporation through a shadow mask. Typical electrodes were of a sizeleading to a channel that was 480 microns wide by about 50 microns long,although due to small channel length variations mobilities werecalculated using individually measured lengths. Devices were then testedfor transistor activity. The transistors prepared using the multicolormask yielded a mobility of 0.8 cm²/V-s.

The fabrication sequence employing a multicolor mask as outlined aboveallows for accurate placement of any number of transparent functionallayers on the substrate even while exposing the substrate to varyingtemperature and solvent treatments. Further, even for large areasubstrates, there are no issues with dimensional distortion of thesubstrate or mechanical alignment errors leading to cumulative andcatastrophic alignment errors. Use of the multicolor mask and visiblelight curable films provides a unique solution to the registrationchallenge without the need for expensive alignment equipment andprocesses.

Example 7 Multicolor Mask Formed by Photolithography Process

In this example a multicolor mask MM-2 was prepared containing threecolor absorbing layers RCA-2, GCA-2, and BCA-2 and planarizing layerP-2, with each color corresponding to an individual functional layer ofan array of thin film transistor devices. This mask was prepared in thesame way as the mask described for Example 2, with the exception thatlaser-written molybdenum masks were prepared for the gate layer (CG-1),semiconductor and dielectric layers (CG-2), and source and drain layers(CG-3) of the array of thin film transistor devices. In addition, thedesired functional layers were encoded into different color records inthis mask than was used for Example 2. That is, red color absorbinglayer RCA-2 was prepared using the cyan photoresist SC32000L and exposedusing mask CG-1. Green color absorbing layer GCA-2 was prepared usingthe magenta photoresist SM3000L, and exposed using mask CG-3. Blue colorabsorbing layer was prepared using yellow photoresist SY3000L, andexposed using mask CG2. The resulting sample was then spin coated (at1000 RPM) with clear photoresist CT2000L, exposed to UV light and bakedfor 5 minutes at 200° C.

The resulting multicolor mask MM-2 contained an array of registered cyan(RCA-2), magenta (GCA-2), and yellow (BCA-2) patterns and a clearplanarizing layer P-2. The absorbance and peak wavelength of theindividual color absorbing layers in MM-2 is shown in Table 2 below. TheOptical Density (Status M) to red light (cyan OD), green (magenta OD),and blue light (yellow OD) and peak wavelength of the individual colorabsorbing layers in MM-2 is shown in Table 2 below.

TABLE 2 Optical Density (Status M) Magenta Yellow Cyan OD (OD) (OD) λmaxBCA-2 0.03 0.05 0.97 465 nm GCA-2 0.05 1.02 0.18 565 nm RCA-2 0.94 0.130.05 625 nm

Example 8

In this set of examples (C4-C12), multicolor mask MM-2 is used incombination with blue, green, and red-sensitive coatings, to producedistinct photopatterns of deposition inhibiting material.

Photopatternable deposition inhibitor coatings C4-C6 were prepared inthe following manner. Coating solutions contained 4 g of CF-3 and 0.5 gof the photoinitiator solution indicated in Table 3 below. The coatingsolution was spin coated at 2000 RPM for one minute and dried for 2minutes at 90° C., loaded in a glass cell purged with nitrogen, andexposed in such fashion that exposing light passed through the supportand multicolor mask MM-2 before reaching the photosensitive coating. Thecoatings were developed using developer solution D-3. These stepsresulted in formation of a negative patterned polymer film correspondingto a specific a color pattern on the multicolor mask. Results aresummarized in Table 3 below. In example C-4, the photopattern producedcorresponded to the blue color absorber pattern BCA-2, establishing thatthis coating formulation is a negative-working, blue sensitive film. Inexample C-5, the photopattern produced corresponded to the green colorabsorber pattern GCA-2, establishing that this coating is anegative-working, green sensitive film. In example C-6, the photopatternproduced corresponded to the red color absorber pattern RCA-2,establishing that this formulation is a negative-working, red sensitivefilm.

Photopatternable deposition inhibitor coatings C7-C9 contained 7 g ofCF-2 and 0.6 g of the photoinitiator solution indicated in Table 3.These solutions were coated, exposed, and developed in the same manneras for examples C4-C6, with the exception that these coatings weredeveloped using developer solution D-2. These steps resulted information of a negative patterned deposition inhibitor filmcorresponding to a specific a color pattern on the multicolor mask, asindicated in Table 3. Coating C10 was exposed using blue light anddeveloped using D-4, forming a positive resist image corresponding toBCA-2.

Photopatternable deposition inhibitor coating C-11 sensitive to bluelight was prepared in the following manner. One gram of CF-6 was dilutedwith 5 g of toluene. The solution was spin coated at 2000 RPM, baked at80° C. for one minute, exposed and developed using developer D-1,forming a negative resist image corresponding to BCA-2.

Photopatternable deposition inhibitor coating C-12 sensitive to bluelight was prepared in the following manner. To 7.65 g of CF-7, 0.06 g ofF-1 were added. The resulting solution was spin coated at 2000 RPM for 1minute, baked at 90° C. for 1 minute, exposed with blue light anddeveloped using developer D-5, rinsed with OCG Rinse, obtained fromFujifilm Electronic Materials, forming a negative resist imagecorresponding to BCA-2.

TABLE 3 Stock Exposing Photopattern Example Solution Photoinitiatorlight obtained C-4 CF-3 YPI-3 Blue BCA-2/negative C-5 CF-3 MPI-3 GreenGCA-2/negative C-6 CF-3 CPI-3 Red RCA-2/negative C-7 CF-2 YPI-2 BlueBCA-2/negative C-8 CF-2 MPI-2 Green GCA-2/negative C-9 CF-2 CPI-2 RedRCA-2/negative C-10 CF-5 As purchased Blue BCA-2/positive C-11 CF-6YPI-1 Blue BCA-2/negative C-12 CF-7 F-1 Blue BCA-2/negative

Examples 9-13 Materials Patterning by Selective Deposition Process

In these examples, a multicolor mask prepared according to the proceduredescribed for Example 7 was used in combination with visible-lightsensitive coating to pattern a materials in selective depositionprocesses. Because the colorants in the_multicolor mask are spectrallydistinct, the desired pattern for the zinc oxide layer was addressedsimply by using an appropriate dye photoinitiator and color of exposinglight.

Example 9 ZnO Selective Deposition

A photopatternable coating sensitive was prepared, exposed, anddeveloped according to the procedure described for coating C-4 above.These steps resulted in formation of a negative patterned polymer filmcorresponding to the blue absorber pattern in the multicolor mask. Afterthe photosensitive coating was developed, a zinc oxide coating wasselectively deposited on regions not masked by the photopatterneddeposition inhibitor. The device used to prepare ZnO layer has beendescribed in detail in U.S. patent application Ser. No. 11/627,525,hereby incorporated by reference in its entirety. A 200-Angstrom thickzinc oxide coating was applied using this ALD coating device withdiethyl zinc and water as reactive materials entrained in a nitrogencarrier gas. Ellipsometry data indicated the ZnO was selectivelydeposited on regions not masked by the photopatterned coating.

Example 10 ZnO Selective Deposition

A photopatternable coating sensitive to blue light was prepared,exposed, and developed according to the procedure described for coatingC-12 above. After the photosensitive coating was developed, a zinc oxidecoating was selectively deposited on regions not masked by thephotopatterned deposition inhibitor, using the same coating device asfor Example 9. For simplicity of reporting, the inhibition power isdefined as the layer thickness at or below which there is substantiallyno thin film formed on the deposition inhibitor surface. Ellipsometrydata indicated the photopatternable coating C-12 had an inhibition powerof 850 Angstroms.

Example 11 Alumina Selective Deposition

A photopatternable coating sensitive to blue light was prepared,exposed, and developed according to the procedure described for coatingC-11 above. These steps resulted in formation of a negative patternedpolymer film corresponding to the blue absorber pattern in themulticolor mask, establishing that this coating formulation is anegative-working, blue sensitive film. After the photosensitive coatingwas developed, an aluminum oxide coating was selectively deposited onregions not masked by the photopatterned deposition inhibitor. Thealumina film was deposited using the same coating device as for Example9, except dimethylaluminum isopropoxide and water were used as reactivematerials entrained in a nitrogen carrier gas. Ellipsometry dataindicated the photopatterned layer had an inhibition power of 500Angstroms.

Examples 12 Selective Deposition of Conducting Film

A photopatternable coating sensitive to green light was prepared,exposed, and developed according to the procedure described for ExampleC-8 above. These steps resulted in formation of a negative patternedpolymer film corresponding to a specific a green-absorbing color patternon the multicolor mask. A layer of silver nanoparticle ink (purchasedfrom Cabot, Albuquerque, N. Mex.) was selectively applied using aninkjet printer, the sample was annealed to form a conducting patternedfilm. Optical micrographs clearly showed the silver pattern formedcorresponded to the green color absorbing pattern, without “spillage”onto the top surface of the photopatterned coating.

Example 13 Selective Area Deposition of Alumina Layer

A photopatternable coating sensitive to blue light was prepared,exposed, and developed according to the procedure described for coatingC-12 above. After the photosensitive coating was developed, an aluminumoxide coating was selectively deposited on regions not masked by thephotopatterned deposition inhibitor, using the same coating device asfor Example 9. For simplicity of reporting, the inhibition power isdefined as the layer thickness at or below which there is substantiallyno thin film formed on the deposition inhibitor surface. Ellipsometrydata indicated the photopatternable coating C-12 had an inhibition powerof 800 Angstroms.

Example 14 Thin Film Transistor by Selective Area Deposition

The first step in fabricating the transistors was to prepare themulticolor mask using the same procedure employed to fabricatemulticolor mask MM-2. In this color mask, the cyan color absorberpattern was a negative of the desired TFT gate pattern. The blue colorabsorber pattern was a positive of the desired TFT gate dielectric andsemiconductor pattern. The green color absorber was a negative of thedesired TFT source/drain/bussing pattern. The sample was coated with1000 Angstroms of sputtered indium-tin-oxide. The ITO gate was patternedusing red-sensitive photopatternable material, employing the coating,exposing, develop, procedure described for Example C-6, etched in E-1,rinsed, and dried. Residual photosensitive material was removed from thesample in an acetone bath and an oxygen plasma treatment. The sample wasthen coated with 1000 Angstroms of aluminum oxide A-2 applied using anatmospheric pressure deposition process. The aluminum oxide dielectricmaterial was patterned using blue-sensitive photosensitive material,employing the coating, exposing, and develop process described forExample C-10. The dielectric layer was subsequently patterned byimmersing the sample in etch bath E-2. Residual photosensitive materialwas removed from the sample in an acetone bath and an oxygen plasmatreatment. The sample was coated with 1000 Angstroms of sputteredindium-tin-oxide. The ITO source, drain, and bussing structure waspatterned using green-sensitive photosensitive material, employing thecoating, exposing, develop, procedure described for Example C-5, etchedin E-1, rinsed, and dried. Residual photosensitive material was removedfrom the sample in an acetone bath and an oxygen plasma treatment. Thezinc oxide semiconductor material was patterned using a blue-sensitivephotocrosslinkable material in a selective deposition process. The samecoating, exposing, develop, and ZnO deposition process was used as wasdescribed for Example 9. Devices were then tested for transistoractivity. The transistors were well isolated, indicating that theselective deposition process employed was effective.

Accordingly, patterned thin films were produced, according to thepresent invention, that function as a deposition inhibitor material andare directly photopatterned using a multicolor mask. The fabricationsequence as outlined above allows for accurate placement of any numberof transparent functional layers on the substrate even while exposingthe substrate to varying temperature and solvent treatments. Further,compared to etch and liftoff patterning processes, the selective areadeposition processes are particularly attractive for building structuredmaterials because they eliminate the need for an etch step, reduce thenumber of cleaning steps required, and may even be used to patternmaterials that are difficult to etch. Even for large area substrates,there are no issues with dimensional distortion of the substrate ormechanical alignment errors leading to cumulative and catastrophicalignment errors. Use of the multicolor mask and visible light curablefilms provides a unique solution to the registration challenge withoutthe need for expensive alignment equipment and processes.

The invention claimed is:
 1. A process for forming a structurecomprising: a) providing a transparent support; b) forming a color mask,having a color pattern, on a first side of the transparent support; c)applying a first layer comprising a deposition inhibitor material thatis sensitive to visible light either on the first side or a sideopposite the first side of the transparent support after forming thecolor mask; d) patterning the first layer comprising the depositioninhibitor material by exposing the first layer through the color maskwith visible light to form a first pattern, wherein the first pattern iscomposed of deposition inhibitor material in a second exposed state thatis different from a first as-coated state, and developing the depositioninhibitor material to provide selected areas of the first layereffectively not having the deposition inhibitor material; and e)depositing a second layer of functional material over the transparentsupport; wherein the second layer of functional material issubstantially deposited only in selected areas over the transparentsupport not having the deposition inhibitor material.
 2. The process ofclaim 1 wherein the selected areas effectively not having the depositioninhibitor material correspond to the portion of the first patterncomposed of the first as-coated state.
 3. The process of claim 1 whereinthe step of depositing the functional material comprises depositing aninorganic thin film over the transparent support by atomic layerdeposition.
 4. The process of claim 3 wherein the step of depositing theinorganic thin film comprises simultaneously directing a series of gasflows, wherein the series of gas flows comprises, in order, at least afirst reactive gaseous material, an inert purge gas, and a secondreactive gaseous material, optionally repeated a plurality of times,wherein the first reactive gaseous material is capable of reacting witha substrate surface treated with the second reactive gaseous material toform the inorganic thin film, wherein the first reactive gaseousmaterial is a volatile organo-metallic precursor compound, wherein theprocess is carried out substantially at or above atmospheric pressurewhile the temperature of the substrate during deposition is under 300°C., and wherein the inorganic thin film is substantially deposited onlyin selected areas of the substrate surface effectively not having thedeposition inhibitor material.
 5. The process of claim 1 where in thedeposition inhibitor material is applied to the first side of thetransparent support, and wherein the color mask, support and thefunctional material in the selected areas remain in the structure. 6.The process of claim 1 further comprising removing the depositioninhibitor material after depositing the functional material.
 7. Theprocess of claim 1 wherein the color mask comprises at least twodifferent color patterns and step (d) uses one of the colored patterns.8. The process of claim 1 wherein the visible light used for exposinghas a spectrum substantially contained within the absorbance spectrum ofthe color mask.
 9. The process of claim 1 wherein the visible light usedfor exposing is white light and the deposition inhibitor material issensitized to the light spectrum filtered by the color mask.
 10. Theprocess of claim 1 wherein the functional material is applied byadditive printing process including gravure or inkjet.
 11. The processof claim 1 wherein the deposition inhibitor comprises a photoinitiatorand a polymeric material.
 12. The process of claim 1 wherein thedeposition inhibitor material comprises a multifunctional acrylateresin.
 13. The process of claim 1 wherein the deposition inhibitormaterial has an inhibition power of at least 50 Å.
 14. The process ofclaim 1 wherein the color mask having the color pattern is formed on thesame side of the transparent support as that on which is applied thefirst layer comprising a deposition inhibitor and on which is depositedthe second layer of functional material, wherein the layer of depositioninhibitor material is positive working or negative working.
 15. Theprocess of claim 1 wherein the color mask having the color pattern isformed on the opposite side of the transparent support from that onwhich is applied the first layer comprising a deposition inhibitor andfrom that on which is deposited the second layer of functional material,wherein the layer of deposition inhibitor material is positive working.